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[PATCH v23 2/8] Row pattern recognition patch (parse/analysis). 187+ messages / 2 participants [nested] [flat]
* [PATCH v23 2/8] Row pattern recognition patch (parse/analysis). @ 2024-10-25 03:56 Tatsuo Ishii <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw) --- src/backend/parser/parse_agg.c | 7 + src/backend/parser/parse_clause.c | 297 +++++++++++++++++++++++++++++- src/backend/parser/parse_expr.c | 6 + src/backend/parser/parse_func.c | 3 + 4 files changed, 312 insertions(+), 1 deletion(-) diff --git a/src/backend/parser/parse_agg.c b/src/backend/parser/parse_agg.c index efa730c167..a80263f90d 100644 --- a/src/backend/parser/parse_agg.c +++ b/src/backend/parser/parse_agg.c @@ -580,6 +580,10 @@ check_agglevels_and_constraints(ParseState *pstate, Node *expr) errkind = true; break; + case EXPR_KIND_RPR_DEFINE: + errkind = true; + break; + /* * There is intentionally no default: case here, so that the * compiler will warn if we add a new ParseExprKind without @@ -970,6 +974,9 @@ transformWindowFuncCall(ParseState *pstate, WindowFunc *wfunc, case EXPR_KIND_CYCLE_MARK: errkind = true; break; + case EXPR_KIND_RPR_DEFINE: + errkind = true; + break; /* * There is intentionally no default: case here, so that the diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c index 4c97690908..a6d2f7f4ba 100644 --- a/src/backend/parser/parse_clause.c +++ b/src/backend/parser/parse_clause.c @@ -98,7 +98,14 @@ static WindowClause *findWindowClause(List *wclist, const char *name); static Node *transformFrameOffset(ParseState *pstate, int frameOptions, Oid rangeopfamily, Oid rangeopcintype, Oid *inRangeFunc, Node *clause); - +static void transformRPR(ParseState *pstate, WindowClause *wc, WindowDef *windef, + List **targetlist); +static List *transformDefineClause(ParseState *pstate, WindowClause *wc, WindowDef *windef, + List **targetlist); +static void transformPatternClause(ParseState *pstate, WindowClause *wc, + WindowDef *windef); +static List *transformMeasureClause(ParseState *pstate, WindowClause *wc, + WindowDef *windef); /* * transformFromClause - @@ -2956,6 +2963,10 @@ transformWindowDefinitions(ParseState *pstate, rangeopfamily, rangeopcintype, &wc->endInRangeFunc, windef->endOffset); + + /* Process Row Pattern Recognition related clauses */ + transformRPR(pstate, wc, windef, targetlist); + wc->winref = winref; result = lappend(result, wc); @@ -3823,3 +3834,287 @@ transformFrameOffset(ParseState *pstate, int frameOptions, return node; } + +/* + * transformRPR + * Process Row Pattern Recognition related clauses + */ +static void +transformRPR(ParseState *pstate, WindowClause *wc, WindowDef *windef, + List **targetlist) +{ + /* + * Window definition exists? + */ + if (windef == NULL) + return; + + /* + * Row Pattern Common Syntax clause exists? + */ + if (windef->rpCommonSyntax == NULL) + return; + + /* Check Frame option. Frame must start at current row */ + if ((wc->frameOptions & FRAMEOPTION_START_CURRENT_ROW) == 0) + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("FRAME must start at current row when row patttern recognition is used"))); + + /* Transform AFTER MACH SKIP TO clause */ + wc->rpSkipTo = windef->rpCommonSyntax->rpSkipTo; + + /* Transform AFTER MACH SKIP TO variable */ + wc->rpSkipVariable = windef->rpCommonSyntax->rpSkipVariable; + + /* Transform SEEK or INITIAL clause */ + wc->initial = windef->rpCommonSyntax->initial; + + /* Transform DEFINE clause into list of TargetEntry's */ + wc->defineClause = transformDefineClause(pstate, wc, windef, targetlist); + + /* Check PATTERN clause and copy to patternClause */ + transformPatternClause(pstate, wc, windef); + + /* Transform MEASURE clause */ + transformMeasureClause(pstate, wc, windef); +} + +/* + * transformDefineClause + * Process DEFINE clause and transform ResTarget into list of + * TargetEntry. + * + * XXX we only support column reference in row pattern definition search + * condition, e.g. "price". <row pattern definition variable name>.<column + * reference> is not supported, e.g. "A.price". + */ +static List * +transformDefineClause(ParseState *pstate, WindowClause *wc, WindowDef *windef, + List **targetlist) +{ + /* DEFINE variable name initials */ + static char *defineVariableInitials = "abcdefghijklmnopqrstuvwxyz"; + + ListCell *lc, + *l; + ResTarget *restarget, + *r; + List *restargets; + List *defineClause; + char *name; + int initialLen; + int i; + + /* + * If Row Definition Common Syntax exists, DEFINE clause must exist. (the + * raw parser should have already checked it.) + */ + Assert(windef->rpCommonSyntax->rpDefs != NULL); + + /* + * Check and add "A AS A IS TRUE" if pattern variable is missing in DEFINE + * per the SQL standard. + */ + restargets = NIL; + foreach(lc, windef->rpCommonSyntax->rpPatterns) + { + A_Expr *a; + bool found = false; + + if (!IsA(lfirst(lc), A_Expr)) + ereport(ERROR, + errmsg("node type is not A_Expr")); + + a = (A_Expr *) lfirst(lc); + name = strVal(a->lexpr); + + foreach(l, windef->rpCommonSyntax->rpDefs) + { + restarget = (ResTarget *) lfirst(l); + + if (!strcmp(restarget->name, name)) + { + found = true; + break; + } + } + + if (!found) + { + /* + * "name" is missing. So create "name AS name IS TRUE" ResTarget + * node and add it to the temporary list. + */ + A_Const *n; + + restarget = makeNode(ResTarget); + n = makeNode(A_Const); + n->val.boolval.type = T_Boolean; + n->val.boolval.boolval = true; + n->location = -1; + restarget->name = pstrdup(name); + restarget->indirection = NIL; + restarget->val = (Node *) n; + restarget->location = -1; + restargets = lappend((List *) restargets, restarget); + } + } + + if (list_length(restargets) >= 1) + { + /* add missing DEFINEs */ + windef->rpCommonSyntax->rpDefs = + list_concat(windef->rpCommonSyntax->rpDefs, restargets); + list_free(restargets); + } + + /* + * Check for duplicate row pattern definition variables. The standard + * requires that no two row pattern definition variable names shall be + * equivalent. + */ + restargets = NIL; + foreach(lc, windef->rpCommonSyntax->rpDefs) + { + restarget = (ResTarget *) lfirst(lc); + name = restarget->name; + + /* + * Add DEFINE expression (Restarget->val) to the targetlist as a + * TargetEntry if it does not exist yet. Planner will add the column + * ref var node to the outer plan's target list later on. This makes + * DEFINE expression could access the outer tuple while evaluating + * PATTERN. + * + * XXX: adding whole expressions of DEFINE to the plan.targetlist is + * not so good, because it's not necessary to evalute the expression + * in the target list while running the plan. We should extract the + * var nodes only then add them to the plan.targetlist. + */ + findTargetlistEntrySQL99(pstate, (Node *) restarget->val, + targetlist, EXPR_KIND_RPR_DEFINE); + + /* + * Make sure that the row pattern definition search condition is a + * boolean expression. + */ + transformWhereClause(pstate, restarget->val, + EXPR_KIND_RPR_DEFINE, "DEFINE"); + + foreach(l, restargets) + { + char *n; + + r = (ResTarget *) lfirst(l); + n = r->name; + + if (!strcmp(n, name)) + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("row pattern definition variable name \"%s\" appears more than once in DEFINE clause", + name), + parser_errposition(pstate, exprLocation((Node *) r)))); + } + restargets = lappend(restargets, restarget); + } + list_free(restargets); + + /* + * Create list of row pattern DEFINE variable name's initial. We assign + * [a-z] to them (up to 26 variable names are allowed). + */ + restargets = NIL; + i = 0; + initialLen = strlen(defineVariableInitials); + + foreach(lc, windef->rpCommonSyntax->rpDefs) + { + char initial[2]; + + restarget = (ResTarget *) lfirst(lc); + name = restarget->name; + + if (i >= initialLen) + { + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("number of row pattern definition variable names exceeds %d", + initialLen), + parser_errposition(pstate, + exprLocation((Node *) restarget)))); + } + initial[0] = defineVariableInitials[i++]; + initial[1] = '\0'; + wc->defineInitial = lappend(wc->defineInitial, + makeString(pstrdup(initial))); + } + + defineClause = transformTargetList(pstate, windef->rpCommonSyntax->rpDefs, + EXPR_KIND_RPR_DEFINE); + + /* mark column origins */ + markTargetListOrigins(pstate, defineClause); + + /* mark all nodes in the DEFINE clause tree with collation information */ + assign_expr_collations(pstate, (Node *) defineClause); + + return defineClause; +} + +/* + * transformPatternClause + * Process PATTERN clause and return PATTERN clause in the raw parse tree + */ +static void +transformPatternClause(ParseState *pstate, WindowClause *wc, + WindowDef *windef) +{ + ListCell *lc; + + /* + * Row Pattern Common Syntax clause exists? + */ + if (windef->rpCommonSyntax == NULL) + return; + + wc->patternVariable = NIL; + wc->patternRegexp = NIL; + foreach(lc, windef->rpCommonSyntax->rpPatterns) + { + A_Expr *a; + char *name; + char *regexp; + + if (!IsA(lfirst(lc), A_Expr)) + ereport(ERROR, + errmsg("node type is not A_Expr")); + + a = (A_Expr *) lfirst(lc); + name = strVal(a->lexpr); + + wc->patternVariable = lappend(wc->patternVariable, makeString(pstrdup(name))); + regexp = strVal(lfirst(list_head(a->name))); + + wc->patternRegexp = lappend(wc->patternRegexp, makeString(pstrdup(regexp))); + } +} + +/* + * transformMeasureClause + * Process MEASURE clause + * XXX MEASURE clause is not supported yet + */ +static List * +transformMeasureClause(ParseState *pstate, WindowClause *wc, + WindowDef *windef) +{ + if (windef->rowPatternMeasures == NIL) + return NIL; + + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("%s", "MEASURE clause is not supported yet"), + parser_errposition(pstate, exprLocation((Node *) windef->rowPatternMeasures)))); + return NIL; +} diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index ef0b560f5e..b30b9f2675 100644 --- a/src/backend/parser/parse_expr.c +++ b/src/backend/parser/parse_expr.c @@ -577,6 +577,7 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref) case EXPR_KIND_COPY_WHERE: case EXPR_KIND_GENERATED_COLUMN: case EXPR_KIND_CYCLE_MARK: + case EXPR_KIND_RPR_DEFINE: /* okay */ break; @@ -1860,6 +1861,9 @@ transformSubLink(ParseState *pstate, SubLink *sublink) case EXPR_KIND_GENERATED_COLUMN: err = _("cannot use subquery in column generation expression"); break; + case EXPR_KIND_RPR_DEFINE: + err = _("cannot use subquery in DEFINE expression"); + break; /* * There is intentionally no default: case here, so that the @@ -3199,6 +3203,8 @@ ParseExprKindName(ParseExprKind exprKind) return "GENERATED AS"; case EXPR_KIND_CYCLE_MARK: return "CYCLE"; + case EXPR_KIND_RPR_DEFINE: + return "DEFINE"; /* * There is intentionally no default: case here, so that the diff --git a/src/backend/parser/parse_func.c b/src/backend/parser/parse_func.c index 9b23344a3b..4c482abb30 100644 --- a/src/backend/parser/parse_func.c +++ b/src/backend/parser/parse_func.c @@ -2658,6 +2658,9 @@ check_srf_call_placement(ParseState *pstate, Node *last_srf, int location) case EXPR_KIND_CYCLE_MARK: errkind = true; break; + case EXPR_KIND_RPR_DEFINE: + errkind = true; + break; /* * There is intentionally no default: case here, so that the -- 2.25.1 ----Next_Part(Fri_Oct_25_13_04_53_2024_648)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v23-0003-Row-pattern-recognition-patch-rewriter.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 187+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 187+ messages in thread
end of thread, other threads:[~2026-04-01 17:54 UTC | newest] Thread overview: 187+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2024-10-25 03:56 [PATCH v23 2/8] Row pattern recognition patch (parse/analysis). Tatsuo Ishii <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]>
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