agora inbox for [email protected]  

help / color / mirror / Atom feed

[PATCH v25 1/9] Row pattern recognition patch for raw parser.
57+ messages / 2 participants
[nested] [flat]

* [PATCH v25 1/9] Row pattern recognition patch for raw parser.
@ 2024-12-21 06:19  Tatsuo Ishii <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)

---
 src/backend/parser/gram.y       | 221 ++++++++++++++++++++++++++++++--
 src/include/nodes/parsenodes.h  |  67 ++++++++++
 src/include/parser/kwlist.h     |   8 ++
 src/include/parser/parse_node.h |   1 +
 4 files changed, 286 insertions(+), 11 deletions(-)

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 67eb96396a..d21dc28955 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -664,6 +664,21 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 				json_object_constructor_null_clause_opt
 				json_array_constructor_null_clause_opt
 
+%type <target>	row_pattern_measure_item
+				row_pattern_definition
+%type <node>	opt_row_pattern_common_syntax
+				opt_row_pattern_skip_to
+				row_pattern_subset_item
+				row_pattern_term
+%type <list>	opt_row_pattern_measures
+				row_pattern_measure_list
+				row_pattern_definition_list
+				opt_row_pattern_subset_clause
+				row_pattern_subset_list
+				row_pattern_subset_rhs
+				row_pattern
+%type <boolean>	opt_row_pattern_initial_or_seek
+				first_or_last
 
 /*
  * Non-keyword token types.  These are hard-wired into the "flex" lexer.
@@ -707,7 +722,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	CURRENT_TIME CURRENT_TIMESTAMP CURRENT_USER CURSOR CYCLE
 
 	DATA_P DATABASE DAY_P DEALLOCATE DEC DECIMAL_P DECLARE DEFAULT DEFAULTS
-	DEFERRABLE DEFERRED DEFINER DELETE_P DELIMITER DELIMITERS DEPENDS DEPTH DESC
+	DEFERRABLE DEFERRED DEFINE DEFINER DELETE_P DELIMITER DELIMITERS DEPENDS DEPTH DESC
 	DETACH DICTIONARY DISABLE_P DISCARD DISTINCT DO DOCUMENT_P DOMAIN_P
 	DOUBLE_P DROP
 
@@ -723,7 +738,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	HANDLER HAVING HEADER_P HOLD HOUR_P
 
 	IDENTITY_P IF_P ILIKE IMMEDIATE IMMUTABLE IMPLICIT_P IMPORT_P IN_P INCLUDE
-	INCLUDING INCREMENT INDENT INDEX INDEXES INHERIT INHERITS INITIALLY INLINE_P
+	INCLUDING INCREMENT INDENT INDEX INDEXES INHERIT INHERITS INITIAL INITIALLY INLINE_P
 	INNER_P INOUT INPUT_P INSENSITIVE INSERT INSTEAD INT_P INTEGER
 	INTERSECT INTERVAL INTO INVOKER IS ISNULL ISOLATION
 
@@ -736,7 +751,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	LEADING LEAKPROOF LEAST LEFT LEVEL LIKE LIMIT LISTEN LOAD LOCAL
 	LOCALTIME LOCALTIMESTAMP LOCATION LOCK_P LOCKED LOGGED
 
-	MAPPING MATCH MATCHED MATERIALIZED MAXVALUE MERGE MERGE_ACTION METHOD
+	MAPPING MATCH MATCHED MATERIALIZED MAXVALUE MEASURES MERGE MERGE_ACTION METHOD
 	MINUTE_P MINVALUE MODE MONTH_P MOVE
 
 	NAME_P NAMES NATIONAL NATURAL NCHAR NESTED NEW NEXT NFC NFD NFKC NFKD NO
@@ -748,8 +763,9 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	ORDER ORDINALITY OTHERS OUT_P OUTER_P
 	OVER OVERLAPS OVERLAY OVERRIDING OWNED OWNER
 
-	PARALLEL PARAMETER PARSER PARTIAL PARTITION PASSING PASSWORD PATH
-	PERIOD PLACING PLAN PLANS POLICY
+	PARALLEL PARAMETER PARSER PARTIAL PARTITION PASSING PASSWORD PAST
+	PATH PATTERN_P PERIOD PERMUTE PLACING PLAN PLANS POLICY
+
 	POSITION PRECEDING PRECISION PRESERVE PREPARE PREPARED PRIMARY
 	PRIOR PRIVILEGES PROCEDURAL PROCEDURE PROCEDURES PROGRAM PUBLICATION
 
@@ -760,12 +776,13 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	RESET RESTART RESTRICT RETURN RETURNING RETURNS REVOKE RIGHT ROLE ROLLBACK ROLLUP
 	ROUTINE ROUTINES ROW ROWS RULE
 
-	SAVEPOINT SCALAR SCHEMA SCHEMAS SCROLL SEARCH SECOND_P SECURITY SELECT
+	SAVEPOINT SCALAR SCHEMA SCHEMAS SCROLL SEARCH SECOND_P SECURITY SEEK SELECT
 	SEQUENCE SEQUENCES
+
 	SERIALIZABLE SERVER SESSION SESSION_USER SET SETS SETOF SHARE SHOW
 	SIMILAR SIMPLE SKIP SMALLINT SNAPSHOT SOME SOURCE SQL_P STABLE STANDALONE_P
 	START STATEMENT STATISTICS STDIN STDOUT STORAGE STORED STRICT_P STRING_P STRIP_P
-	SUBSCRIPTION SUBSTRING SUPPORT SYMMETRIC SYSID SYSTEM_P SYSTEM_USER
+	SUBSCRIPTION SUBSET SUBSTRING SUPPORT SYMMETRIC SYSID SYSTEM_P SYSTEM_USER
 
 	TABLE TABLES TABLESAMPLE TABLESPACE TARGET TEMP TEMPLATE TEMPORARY TEXT_P THEN
 	TIES TIME TIMESTAMP TO TRAILING TRANSACTION TRANSFORM
@@ -874,6 +891,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %nonassoc	UNBOUNDED NESTED /* ideally would have same precedence as IDENT */
 %nonassoc	IDENT PARTITION RANGE ROWS GROUPS PRECEDING FOLLOWING CUBE ROLLUP
 			SET KEYS OBJECT_P SCALAR VALUE_P WITH WITHOUT PATH
+			MEASURES AFTER INITIAL SEEK PATTERN_P
 %left		Op OPERATOR		/* multi-character ops and user-defined operators */
 %left		'+' '-'
 %left		'*' '/' '%'
@@ -16326,7 +16344,8 @@ over_clause: OVER window_specification
 		;
 
 window_specification: '(' opt_existing_window_name opt_partition_clause
-						opt_sort_clause opt_frame_clause ')'
+						opt_sort_clause opt_row_pattern_measures opt_frame_clause
+						opt_row_pattern_common_syntax ')'
 				{
 					WindowDef  *n = makeNode(WindowDef);
 
@@ -16334,10 +16353,12 @@ window_specification: '(' opt_existing_window_name opt_partition_clause
 					n->refname = $2;
 					n->partitionClause = $3;
 					n->orderClause = $4;
+					n->rowPatternMeasures = $5;
 					/* copy relevant fields of opt_frame_clause */
-					n->frameOptions = $5->frameOptions;
-					n->startOffset = $5->startOffset;
-					n->endOffset = $5->endOffset;
+					n->frameOptions = $6->frameOptions;
+					n->startOffset = $6->startOffset;
+					n->endOffset = $6->endOffset;
+					n->rpCommonSyntax = (RPCommonSyntax *)$7;
 					n->location = @1;
 					$$ = n;
 				}
@@ -16361,6 +16382,31 @@ opt_partition_clause: PARTITION BY expr_list		{ $$ = $3; }
 			| /*EMPTY*/								{ $$ = NIL; }
 		;
 
+/*
+ * ROW PATTERN_P MEASURES
+ */
+opt_row_pattern_measures: MEASURES row_pattern_measure_list	{ $$ = $2; }
+			| /*EMPTY*/								{ $$ = NIL; }
+		;
+
+row_pattern_measure_list:
+			row_pattern_measure_item
+					{ $$ = list_make1($1); }
+			| row_pattern_measure_list ',' row_pattern_measure_item
+					{ $$ = lappend($1, $3); }
+		;
+
+row_pattern_measure_item:
+			a_expr AS ColLabel
+				{
+					$$ = makeNode(ResTarget);
+					$$->name = $3;
+					$$->indirection = NIL;
+					$$->val = (Node *) $1;
+					$$->location = @1;
+				}
+		;
+
 /*
  * For frame clauses, we return a WindowDef, but only some fields are used:
  * frameOptions, startOffset, and endOffset.
@@ -16520,6 +16566,143 @@ opt_window_exclusion_clause:
 			| /*EMPTY*/				{ $$ = 0; }
 		;
 
+opt_row_pattern_common_syntax:
+opt_row_pattern_skip_to opt_row_pattern_initial_or_seek
+				PATTERN_P '(' row_pattern ')'
+				opt_row_pattern_subset_clause
+				DEFINE row_pattern_definition_list
+			{
+				RPCommonSyntax *n = makeNode(RPCommonSyntax);
+				n->rpSkipTo = ((RPCommonSyntax *)$1)->rpSkipTo;
+				n->rpSkipVariable = ((RPCommonSyntax *)$1)->rpSkipVariable;
+				n->initial = $2;
+				n->rpPatterns = $5;
+				n->rpSubsetClause = $7;
+				n->rpDefs = $9;
+				$$ = (Node *) n;
+			}
+			| /*EMPTY*/		{ $$ = NULL; }
+	;
+
+opt_row_pattern_skip_to:
+			AFTER MATCH SKIP TO NEXT ROW
+				{
+					RPCommonSyntax *n = makeNode(RPCommonSyntax);
+					n->rpSkipTo = ST_NEXT_ROW;
+					n->rpSkipVariable = NULL;
+					$$ = (Node *) n;
+			}
+			| AFTER MATCH SKIP PAST LAST_P ROW
+				{
+					RPCommonSyntax *n = makeNode(RPCommonSyntax);
+					n->rpSkipTo = ST_PAST_LAST_ROW;
+					n->rpSkipVariable = NULL;
+					$$ = (Node *) n;
+				}
+			| AFTER MATCH SKIP TO first_or_last ColId
+				{
+					RPCommonSyntax *n = makeNode(RPCommonSyntax);
+					n->rpSkipTo = $5? ST_FIRST_VARIABLE : ST_LAST_VARIABLE;
+					n->rpSkipVariable = $6;
+					$$ = (Node *) n;
+				}
+/*
+			| AFTER MATCH SKIP TO LAST_P ColId		%prec LAST_P
+				{
+					RPCommonSyntax *n = makeNode(RPCommonSyntax);
+					n->rpSkipTo = ST_LAST_VARIABLE;
+					n->rpSkipVariable = $6;
+					$$ = n;
+				}
+			| AFTER MATCH SKIP TO ColId
+				{
+					RPCommonSyntax *n = makeNode(RPCommonSyntax);
+					n->rpSkipTo = ST_VARIABLE;
+					n->rpSkipVariable = $5;
+					$$ = n;
+				}
+*/
+			| /*EMPTY*/
+				{
+					RPCommonSyntax *n = makeNode(RPCommonSyntax);
+					/* temporary set default to ST_NEXT_ROW */
+					n->rpSkipTo = ST_PAST_LAST_ROW;
+					n->rpSkipVariable = NULL;
+					$$ = (Node *) n;
+				}
+	;
+
+first_or_last:
+			FIRST_P		{ $$ = true; }
+			| LAST_P	{ $$ = false; }
+	;
+
+opt_row_pattern_initial_or_seek:
+			INITIAL			{ $$ = true; }
+			| SEEK
+				{
+					ereport(ERROR,
+							(errcode(ERRCODE_SYNTAX_ERROR),
+							 errmsg("SEEK is not supported"),
+							 errhint("Use INITIAL."),
+							 parser_errposition(@1)));
+				}
+			| /*EMPTY*/		{ $$ = true; }
+		;
+
+row_pattern:
+			row_pattern_term							{ $$ = list_make1($1); }
+			| row_pattern row_pattern_term				{ $$ = lappend($1, $2); }
+		;
+
+row_pattern_term:
+			ColId	{ $$ = (Node *) makeSimpleA_Expr(AEXPR_OP, "", (Node *)makeString($1), NULL, @1); }
+			| ColId '*'	{ $$ = (Node *) makeSimpleA_Expr(AEXPR_OP, "*", (Node *)makeString($1), NULL, @1); }
+			| ColId '+'	{ $$ = (Node *) makeSimpleA_Expr(AEXPR_OP, "+", (Node *)makeString($1), NULL, @1); }
+			| ColId '?'	{ $$ = (Node *) makeSimpleA_Expr(AEXPR_OP, "?", (Node *)makeString($1), NULL, @1); }
+		;
+
+opt_row_pattern_subset_clause:
+			SUBSET row_pattern_subset_list	{ $$ = $2; }
+			| /*EMPTY*/												{ $$ = NIL; }
+		;
+
+row_pattern_subset_list:
+			row_pattern_subset_item									{ $$ = list_make1($1); }
+			| row_pattern_subset_list ',' row_pattern_subset_item	{ $$ = lappend($1, $3); }
+			| /*EMPTY*/												{ $$ = NIL; }
+		;
+
+row_pattern_subset_item: ColId '=' '(' row_pattern_subset_rhs ')'
+			{
+				RPSubsetItem *n = makeNode(RPSubsetItem);
+				n->name = $1;
+				n->rhsVariable = $4;
+				$$ = (Node *) n;
+			}
+		;
+
+row_pattern_subset_rhs:
+			ColId								{ $$ = list_make1(makeStringConst($1, @1)); }
+			| row_pattern_subset_rhs ',' ColId	{ $$ = lappend($1, makeStringConst($3, @1)); }
+			| /*EMPTY*/							{ $$ = NIL; }
+		;
+
+row_pattern_definition_list:
+			row_pattern_definition										{ $$ = list_make1($1); }
+			| row_pattern_definition_list ',' row_pattern_definition	{ $$ = lappend($1, $3); }
+		;
+
+row_pattern_definition:
+			ColId AS a_expr
+				{
+					$$ = makeNode(ResTarget);
+					$$->name = $1;
+					$$->indirection = NIL;
+					$$->val = (Node *) $3;
+					$$->location = @1;
+				}
+		;
 
 /*
  * Supporting nonterminals for expressions.
@@ -17732,6 +17915,7 @@ unreserved_keyword:
 			| INDEXES
 			| INHERIT
 			| INHERITS
+			| INITIAL
 			| INLINE_P
 			| INPUT_P
 			| INSENSITIVE
@@ -17760,6 +17944,7 @@ unreserved_keyword:
 			| MATCHED
 			| MATERIALIZED
 			| MAXVALUE
+			| MEASURES
 			| MERGE
 			| METHOD
 			| MINUTE_P
@@ -17804,8 +17989,11 @@ unreserved_keyword:
 			| PARTITION
 			| PASSING
 			| PASSWORD
+			| PAST
 			| PATH
+			| PATTERN_P
 			| PERIOD
+			| PERMUTE
 			| PLAN
 			| PLANS
 			| POLICY
@@ -17857,6 +18045,7 @@ unreserved_keyword:
 			| SEARCH
 			| SECOND_P
 			| SECURITY
+			| SEEK
 			| SEQUENCE
 			| SEQUENCES
 			| SERIALIZABLE
@@ -17884,6 +18073,7 @@ unreserved_keyword:
 			| STRING_P
 			| STRIP_P
 			| SUBSCRIPTION
+			| SUBSET
 			| SUPPORT
 			| SYSID
 			| SYSTEM_P
@@ -18078,6 +18268,7 @@ reserved_keyword:
 			| CURRENT_USER
 			| DEFAULT
 			| DEFERRABLE
+			| DEFINE
 			| DESC
 			| DISTINCT
 			| DO
@@ -18241,6 +18432,7 @@ bare_label_keyword:
 			| DEFAULTS
 			| DEFERRABLE
 			| DEFERRED
+			| DEFINE
 			| DEFINER
 			| DELETE_P
 			| DELIMITER
@@ -18318,6 +18510,7 @@ bare_label_keyword:
 			| INDEXES
 			| INHERIT
 			| INHERITS
+			| INITIAL
 			| INITIALLY
 			| INLINE_P
 			| INNER_P
@@ -18372,6 +18565,7 @@ bare_label_keyword:
 			| MATCHED
 			| MATERIALIZED
 			| MAXVALUE
+			| MEASURES
 			| MERGE
 			| MERGE_ACTION
 			| METHOD
@@ -18428,8 +18622,11 @@ bare_label_keyword:
 			| PARTITION
 			| PASSING
 			| PASSWORD
+			| PAST
 			| PATH
+			| PATTERN_P
 			| PERIOD
+			| PERMUTE
 			| PLACING
 			| PLAN
 			| PLANS
@@ -18487,6 +18684,7 @@ bare_label_keyword:
 			| SCROLL
 			| SEARCH
 			| SECURITY
+			| SEEK
 			| SELECT
 			| SEQUENCE
 			| SEQUENCES
@@ -18520,6 +18718,7 @@ bare_label_keyword:
 			| STRING_P
 			| STRIP_P
 			| SUBSCRIPTION
+			| SUBSET
 			| SUBSTRING
 			| SUPPORT
 			| SYMMETRIC
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 0f9462493e..defc62bf9b 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -552,6 +552,48 @@ typedef struct SortBy
 	ParseLoc	location;		/* operator location, or -1 if none/unknown */
 } SortBy;
 
+/*
+ * AFTER MATCH row pattern skip to types in row pattern common syntax
+ */
+typedef enum RPSkipTo
+{
+	ST_NONE,					/* AFTER MATCH omitted */
+	ST_NEXT_ROW,				/* SKIP TO NEXT ROW */
+	ST_PAST_LAST_ROW,			/* SKIP TO PAST LAST ROW */
+	ST_FIRST_VARIABLE,			/* SKIP TO FIRST variable name */
+	ST_LAST_VARIABLE,			/* SKIP TO LAST variable name */
+	ST_VARIABLE					/* SKIP TO variable name */
+} RPSkipTo;
+
+/*
+ * Row Pattern SUBSET clause item
+ */
+typedef struct RPSubsetItem
+{
+	NodeTag		type;
+	char	   *name;			/* Row Pattern SUBSET clause variable name */
+	List	   *rhsVariable;	/* Row Pattern SUBSET rhs variables (list of
+								 * char *string) */
+} RPSubsetItem;
+
+/*
+ * RowPatternCommonSyntax - raw representation of row pattern common syntax
+ *
+ */
+typedef struct RPCommonSyntax
+{
+	NodeTag		type;
+	RPSkipTo	rpSkipTo;		/* Row Pattern AFTER MATCH SKIP type */
+	char	   *rpSkipVariable; /* Row Pattern Skip To variable name, if any */
+	bool		initial;		/* true if <row pattern initial or seek> is
+								 * initial */
+	List	   *rpPatterns;		/* PATTERN variables (list of A_Expr) */
+	List	   *rpSubsetClause; /* row pattern subset clause (list of
+								 * RPSubsetItem), if any */
+	List	   *rpDefs;			/* row pattern definitions clause (list of
+								 * ResTarget) */
+} RPCommonSyntax;
+
 /*
  * WindowDef - raw representation of WINDOW and OVER clauses
  *
@@ -567,6 +609,9 @@ typedef struct WindowDef
 	char	   *refname;		/* referenced window name, if any */
 	List	   *partitionClause;	/* PARTITION BY expression list */
 	List	   *orderClause;	/* ORDER BY (list of SortBy) */
+	List	   *rowPatternMeasures; /* row pattern measures (list of
+									 * ResTarget) */
+	RPCommonSyntax *rpCommonSyntax; /* row pattern common syntax */
 	int			frameOptions;	/* frame_clause options, see below */
 	Node	   *startOffset;	/* expression for starting bound, if any */
 	Node	   *endOffset;		/* expression for ending bound, if any */
@@ -1530,6 +1575,11 @@ typedef struct GroupingSet
  * the orderClause might or might not be copied (see copiedOrder); the framing
  * options are never copied, per spec.
  *
+ * "defineClause" is Row Pattern Recognition DEFINE clause (list of
+ * TargetEntry). TargetEntry.resname represents row pattern definition
+ * variable name. "patternVariable" and "patternRegexp" represents PATTERN
+ * clause.
+ *
  * The information relevant for the query jumbling is the partition clause
  * type and its bounds.
  */
@@ -1559,6 +1609,23 @@ typedef struct WindowClause
 	Index		winref;			/* ID referenced by window functions */
 	/* did we copy orderClause from refname? */
 	bool		copiedOrder pg_node_attr(query_jumble_ignore);
+	/* Row Pattern AFTER MACH SKIP clause */
+	RPSkipTo	rpSkipTo;		/* Row Pattern Skip To type */
+	char	   *rpSkipVariable; /* Row Pattern Skip To variable */
+	bool		initial;		/* true if <row pattern initial or seek> is
+								 * initial */
+	/* Row Pattern DEFINE clause (list of TargetEntry) */
+	List	   *defineClause;
+	/* Row Pattern DEFINE variable initial names (list of String) */
+	List	   *defineInitial;
+	/* Row Pattern PATTERN variable name (list of String) */
+	List	   *patternVariable;
+
+	/*
+	 * Row Pattern PATTERN regular expression quantifier ('+' or ''. list of
+	 * String)
+	 */
+	List	   *patternRegexp;
 } WindowClause;
 
 /*
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index 899d64ad55..f52d797615 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -129,6 +129,7 @@ PG_KEYWORD("default", DEFAULT, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("defaults", DEFAULTS, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("deferrable", DEFERRABLE, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("deferred", DEFERRED, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("define", DEFINE, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("definer", DEFINER, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("delete", DELETE_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("delimiter", DELIMITER, UNRESERVED_KEYWORD, BARE_LABEL)
@@ -215,6 +216,7 @@ PG_KEYWORD("index", INDEX, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("indexes", INDEXES, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("inherit", INHERIT, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("inherits", INHERITS, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("initial", INITIAL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("initially", INITIALLY, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("inline", INLINE_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("inner", INNER_P, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
@@ -273,6 +275,7 @@ PG_KEYWORD("match", MATCH, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("matched", MATCHED, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("materialized", MATERIALIZED, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("maxvalue", MAXVALUE, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("measures", MEASURES, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("merge", MERGE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("merge_action", MERGE_ACTION, COL_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("method", METHOD, UNRESERVED_KEYWORD, BARE_LABEL)
@@ -337,8 +340,11 @@ PG_KEYWORD("partial", PARTIAL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("partition", PARTITION, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("passing", PASSING, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("password", PASSWORD, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("past", PAST, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("path", PATH, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("pattern", PATTERN_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("period", PERIOD, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("permute", PERMUTE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("placing", PLACING, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("plan", PLAN, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("plans", PLANS, UNRESERVED_KEYWORD, BARE_LABEL)
@@ -399,6 +405,7 @@ PG_KEYWORD("scroll", SCROLL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("search", SEARCH, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("second", SECOND_P, UNRESERVED_KEYWORD, AS_LABEL)
 PG_KEYWORD("security", SECURITY, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("seek", SEEK, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("select", SELECT, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("sequence", SEQUENCE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("sequences", SEQUENCES, UNRESERVED_KEYWORD, BARE_LABEL)
@@ -432,6 +439,7 @@ PG_KEYWORD("strict", STRICT_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("string", STRING_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("strip", STRIP_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("subscription", SUBSCRIPTION, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("subset", SUBSET, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("substring", SUBSTRING, COL_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("support", SUPPORT, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("symmetric", SYMMETRIC, RESERVED_KEYWORD, BARE_LABEL)
diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h
index 2375e95c10..737f8a9e0e 100644
--- a/src/include/parser/parse_node.h
+++ b/src/include/parser/parse_node.h
@@ -51,6 +51,7 @@ typedef enum ParseExprKind
 	EXPR_KIND_WINDOW_FRAME_RANGE,	/* window frame clause with RANGE */
 	EXPR_KIND_WINDOW_FRAME_ROWS,	/* window frame clause with ROWS */
 	EXPR_KIND_WINDOW_FRAME_GROUPS,	/* window frame clause with GROUPS */
+	EXPR_KIND_RPR_DEFINE,		/* DEFINE */
 	EXPR_KIND_SELECT_TARGET,	/* SELECT target list item */
 	EXPR_KIND_INSERT_TARGET,	/* INSERT target list item */
 	EXPR_KIND_UPDATE_SOURCE,	/* UPDATE assignment source item */
-- 
2.25.1


----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v25-0002-Row-pattern-recognition-patch-parse-analysis.patch"



^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH 2/2] Publish list of tables being repacked in shared memory
@ 2026-04-07 20:29  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Álvaro Herrera @ 2026-04-07 20:29 UTC (permalink / raw)

Use it in autovacuum to skip processing tables that are being repacked.
This is mostly to avoid repeated attempts to process such tables, which
would fail due to the special deadlock checker behavior for repack.

Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/commands/repack.c                 | 195 ++++++++++++++++--
 src/backend/postmaster/autovacuum.c           |  20 ++
 .../utils/activity/wait_event_names.txt       |   1 +
 src/include/commands/repack.h                 |   2 +
 src/include/storage/lwlocklist.h              |   2 +-
 src/include/storage/subsystemlist.h           |   1 +
 src/tools/pgindent/typedefs.list              |   3 +
 7 files changed, 210 insertions(+), 14 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index a5f5df77291..ee7072dce6a 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -63,9 +63,11 @@
 #include "optimizer/optimizer.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "storage/subsystems.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -79,6 +81,32 @@
 #include "utils/syscache.h"
 #include "utils/wait_event_types.h"
 
+
+/* Shared memory layout for REPACK */
+typedef struct RepackWorkerInfo
+{
+	bool		ri_in_use;
+	pid_t		ri_backendpid;
+	Oid			ri_dbid;
+	Oid			ri_relid;
+	Oid			ri_toastrelid;
+} RepackWorkerInfo;
+
+typedef struct
+{
+	bool		re_useless;
+	RepackWorkerInfo re_workerinfo[FLEXIBLE_ARRAY_MEMBER];
+} RepackShmemStruct;
+
+static RepackShmemStruct *RepackShmem;
+
+typedef struct RepackCleanupContext
+{
+	bool		concurrent;
+	int			workerindex;
+} RepackCleanupContext;
+
+
 /*
  * This struct is used to pass around the information on tables to be
  * clustered. We need this so we can make a list of them when invoked without
@@ -90,6 +118,7 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
+
 /*
  * The first file exported by the decoding worker must contain a snapshot, the
  * following ones contain the data changes.
@@ -166,6 +195,10 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 											  MemoryContext permcxt);
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
+static void RepackCleanup(RepackCleanupContext *context);
+static void RepackCleanupCb(int code, Datum arg);
+static void RepackShmemRequest(void *arg);
+static void RepackShmemInit(void *arg);
 
 static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
@@ -210,6 +243,11 @@ static void ProcessRepackMessage(StringInfo msg);
 static const char *RepackCommandAsString(RepackCommand cmd);
 
 
+const ShmemCallbacks RepackShmemCallbacks = {
+	.request_fn = RepackShmemRequest,
+	.init_fn = RepackShmemInit,
+};
+
 /*
  * The repack code allows for processing multiple tables at once. Because
  * of this, we cannot just run everything on a single transaction, or we
@@ -514,6 +552,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
+	RepackCleanupContext context;
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
@@ -660,24 +699,43 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	PG_TRY();
-	{
-		rebuild_relation(OldHeap, index, verbose, ident_idx);
-	}
-	PG_FINALLY();
+	context.concurrent = concurrent;
+
+	PG_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
 	{
 		if (concurrent)
 		{
-			/*
-			 * Since during normal operation the worker was already asked to
-			 * exit, stopping it explicitly is especially important on ERROR.
-			 * However it still seems a good practice to make sure that the
-			 * worker never survives the REPACK command.
-			 */
-			stop_repack_decoding_worker();
+			bool		freefound = false;
+
+			LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+			for (int i = 0; i < max_repack_replication_slots; i++)
+			{
+				RepackWorkerInfo *worker;
+
+				if (RepackShmem->re_workerinfo[i].ri_in_use)
+					continue;
+
+				freefound = true;
+				worker = &RepackShmem->re_workerinfo[i];
+				context.workerindex = i;
+
+				worker->ri_in_use = true;
+				worker->ri_backendpid = MyProcPid;
+				worker->ri_dbid = MyDatabaseId;
+				worker->ri_relid = RelationGetRelid(OldHeap);
+				worker->ri_toastrelid = OldHeap->rd_rel->reltoastrelid;
+				break;
+			}
+			if (!freefound)
+				elog(ERROR, "could not find free repack entry");
+			LWLockRelease(RepackLock);
 		}
+
+		rebuild_relation(OldHeap, index, verbose, ident_idx);
 	}
-	PG_END_TRY();
+	PG_END_ENSURE_ERROR_CLEANUP(RepackCleanupCb, PointerGetDatum(&context));
+
+	RepackCleanup(&context);
 
 	/* rebuild_relation closes OldHeap, and index if valid */
 
@@ -691,6 +749,117 @@ out:
 	pgstat_progress_end_command();
 }
 
+/*
+ * Return whether any backend is running concurrent REPACK on the given table
+ * (which could be a toast table).
+ */
+bool
+is_table_under_repack(Oid databaseId, Oid relid)
+{
+	bool		retval = false;
+
+	LWLockAcquire(RepackLock, LW_SHARED);
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		RepackWorkerInfo *rworker;
+
+		if (!RepackShmem->re_workerinfo[i].ri_in_use)
+			continue;
+
+		rworker = &RepackShmem->re_workerinfo[i];
+		if (rworker->ri_dbid == MyDatabaseId &&
+			(rworker->ri_relid == relid ||
+			 rworker->ri_toastrelid == relid))
+			retval = true;
+	}
+	LWLockRelease(RepackLock);
+
+	return retval;
+}
+
+/*
+ * Remove ourselves from the workerinfo array.
+ */
+static void
+RepackCleanup(RepackCleanupContext *context)
+{
+	if (context->concurrent)
+	{
+		RepackWorkerInfo *worker;
+
+		/*
+		 * The worker would normally terminate on its own when the work is
+		 * done, but make sure we signal it just in case.
+		 */
+		stop_repack_decoding_worker();
+
+		/*
+		 * also, make sure we stop advertising the relation we were repacking,
+		 * so that autovacuum reverts to handling it normally.
+		 */
+		LWLockAcquire(RepackLock, LW_EXCLUSIVE);
+
+		worker = &RepackShmem->re_workerinfo[context->workerindex];
+		Assert(worker->ri_backendpid == MyProcPid);
+		worker->ri_in_use = false;
+		worker->ri_backendpid = 0;
+		worker->ri_dbid = InvalidOid;
+		worker->ri_relid = InvalidOid;
+		worker->ri_toastrelid = InvalidOid;
+		LWLockRelease(RepackLock);
+	}
+}
+
+/*
+ * RepackCleanup wrapped as an on_shmem_exit callback function
+ */
+static void
+RepackCleanupCb(int code, Datum arg)
+{
+	RepackCleanup((RepackCleanupContext *) DatumGetPointer(arg));
+}
+
+/*
+ * RepackShmemRequest
+ *		Register shared memory space needed for repack
+ */
+static void
+RepackShmemRequest(void *arg)
+{
+	Size		size;
+
+	/*
+	 * Need the fixed struct and the array of RepackWorkerInfo.
+	 */
+	size = sizeof(RepackShmemStruct);
+	size = MAXALIGN(size);
+	size = add_size(size, mul_size(max_repack_replication_slots,
+								   sizeof(RepackWorkerInfo)));
+
+	ShmemRequestStruct(.name = "Repack Data",
+					   .size = size,
+					   .ptr = (void **) &RepackShmem,
+		);
+}
+
+static void
+RepackShmemInit(void *arg)
+{
+	RepackWorkerInfo *reinfo;
+
+	reinfo = (RepackWorkerInfo *) ((char *) RepackShmem +
+								   MAXALIGN(sizeof(RepackShmemStruct)));
+
+	for (int i = 0; i < max_repack_replication_slots; i++)
+	{
+		reinfo[i].ri_in_use = false;
+		reinfo[i].ri_backendpid = 0;
+		reinfo[i].ri_dbid = InvalidOid;
+		reinfo[i].ri_relid = InvalidOid;
+		reinfo[i].ri_toastrelid = InvalidOid;
+	}
+}
+
 /*
  * Check if the table (and its index) still meets the requirements of
  * cluster_rel().
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index bd626a16363..080c64ea3c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -78,6 +78,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_namespace.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -2422,6 +2423,25 @@ do_autovacuum(void)
 			}
 		}
 		LWLockRelease(AutovacuumLock);
+
+		/*
+		 * Similarly, if the table is being processed by concurrent repack,
+		 * skip it (but make a note of that).  We wouldn't be able to acquire
+		 * its lock anyway.
+		 */
+		if (!skipit)
+		{
+			MemoryContextSwitchTo(PortalContext);
+
+			skipit = is_table_under_repack(MyDatabaseId, relid);
+			if (skipit)
+				ereport(LOG,
+						errmsg("skipping table \"%s.%s.%s\" because it's being repacked in concurrent mode",
+							   get_database_name(MyDatabaseId),
+							   get_namespace_name(get_rel_namespace(relid)),
+							   get_rel_name(relid)));
+		}
+
 		if (skipit)
 		{
 			LWLockRelease(AutovacuumScheduleLock);
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7bda5298558..e206304f204 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -332,6 +332,7 @@ SInvalWrite	"Waiting to add a message to the shared catalog invalidation queue."
 WALBufMapping	"Waiting to replace a page in WAL buffers."
 WALWrite	"Waiting for WAL buffers to be written to disk."
 ControlFile	"Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file."
+Repack	"Waiting to read or update tables in process by concurrent repack."
 MultiXactGen	"Waiting to read or update shared multixact state."
 RelCacheInit	"Waiting to read or update a <filename>pg_internal.init</filename> relation cache initialization file."
 CheckpointerComm	"Waiting to manage fsync requests."
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index fd16e74b179..be7d38b5fae 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -42,6 +42,8 @@ extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
 extern void cluster_rel(RepackCommand command, Relation OldHeap, Oid indexOid,
 						ClusterParams *params, bool isTopLevel);
+extern bool is_table_under_repack(Oid databaseId, Oid relid);
+
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
diff --git a/src/include/storage/lwlocklist.h b/src/include/storage/lwlocklist.h
index af8553bcb6c..3f08f4a15d4 100644
--- a/src/include/storage/lwlocklist.h
+++ b/src/include/storage/lwlocklist.h
@@ -41,7 +41,7 @@ PG_LWLOCK(6, SInvalWrite)
 PG_LWLOCK(7, WALBufMapping)
 PG_LWLOCK(8, WALWrite)
 PG_LWLOCK(9, ControlFile)
-/* 10 was CheckpointLock */
+PG_LWLOCK(10, Repack)
 /* 11 was XactSLRULock */
 /* 12 was SubtransSLRULock */
 PG_LWLOCK(13, MultiXactGen)
diff --git a/src/include/storage/subsystemlist.h b/src/include/storage/subsystemlist.h
index 9ad619080be..4e683b8b0a8 100644
--- a/src/include/storage/subsystemlist.h
+++ b/src/include/storage/subsystemlist.h
@@ -72,6 +72,7 @@ PG_SHMEM_SUBSYSTEM(WalSummarizerShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(PgArchShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(ApplyLauncherShmemCallbacks)
 PG_SHMEM_SUBSYSTEM(SlotSyncShmemCallbacks)
+PG_SHMEM_SUBSYSTEM(RepackShmemCallbacks)
 
 /* other modules that need some shared memory space */
 PG_SHMEM_SUBSYSTEM(BTreeShmemCallbacks)
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 637c669a146..d019e03aaf1 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2639,9 +2639,12 @@ ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
+RepackCleanupContext
 RepackCommand
 RepackDecodingState
+RepackShmemStruct
 RepackStmt
+RepackWorkerInfo
 ReparameterizeForeignPathByChild_function
 ReplOriginId
 ReplOriginXactState
-- 
2.47.3


--kdrcpfmkbkc4lqhu--





^ permalink  raw  reply  [nested|flat] 57+ messages in thread