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[PATCH 2/4] Write WAL for empty nbtree index build
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* [PATCH 2/4] Write WAL for empty nbtree index build
@ 2018-10-11 01:03  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 5+ messages in thread

From: Kyotaro Horiguchi @ 2018-10-11 01:03 UTC (permalink / raw)

After relation truncation indexes are also rebuild. It doesn't emit
WAL in minimal mode and if truncation happened within its creation
transaction, crash recovery leaves an empty index heap, which is
considered broken. This patch forces to emit WAL when an index_build
turns into empty nbtree index.
---
 src/backend/access/nbtree/nbtsort.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/backend/access/nbtree/nbtsort.c b/src/backend/access/nbtree/nbtsort.c
index dc398e1186..70d4380533 100644
--- a/src/backend/access/nbtree/nbtsort.c
+++ b/src/backend/access/nbtree/nbtsort.c
@@ -611,8 +611,14 @@ _bt_blwritepage(BTWriteState *wstate, Page page, BlockNumber blkno)
 	/* Ensure rd_smgr is open (could have been closed by relcache flush!) */
 	RelationOpenSmgr(wstate->index);
 
-	/* XLOG stuff */
-	if (wstate->btws_use_wal)
+	/* XLOG stuff
+	 *
+	 * Even if minimal mode, WAL is required here if truncation happened after
+	 * being created in the same transaction. It is not needed otherwise but
+	 * we don't bother identifying the case precisely.
+	 */
+	if (wstate->btws_use_wal ||
+		(blkno == BTREE_METAPAGE && BTPageGetMeta(page)->btm_root == 0))
 	{
 		/* We use the heap NEWPAGE record type for this */
 		log_newpage(&wstate->index->rd_node, MAIN_FORKNUM, blkno, page, true);
@@ -1056,6 +1062,11 @@ _bt_uppershutdown(BTWriteState *wstate, BTPageState *state)
 	 * set to point to "P_NONE").  This changes the index to the "valid" state
 	 * by filling in a valid magic number in the metapage.
 	 */
+	/*
+	 * If no tuple was inserted, it's possible that we are truncating a
+	 * relation. We need to emit WAL for the metapage in the case. However it
+	 * is not required elsewise,
+	 */
 	metapage = (Page) palloc(BLCKSZ);
 	_bt_initmetapage(metapage, rootblkno, rootlevel);
 	_bt_blwritepage(wstate, metapage, BTREE_METAPAGE);
-- 
2.16.3


----Next_Part(Mon_Mar_04_12_24_48_2019_788)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v7-0003-Add-infrastructure-to-WAL-logging-skip-feature.patch"



^ permalink  raw  reply  [nested|flat] 5+ messages in thread

* [PATCH v11 2/7] Row pattern recognition patch (parse/analysis).
@ 2023-11-08 06:57  Tatsuo Ishii <[email protected]>
  0 siblings, 0 replies; 5+ messages in thread

From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)

---
 src/backend/parser/parse_agg.c    |   7 +
 src/backend/parser/parse_clause.c | 278 +++++++++++++++++++++++++++++-
 src/backend/parser/parse_expr.c   |   4 +
 src/backend/parser/parse_func.c   |   3 +
 4 files changed, 291 insertions(+), 1 deletion(-)

diff --git a/src/backend/parser/parse_agg.c b/src/backend/parser/parse_agg.c
index 9bbad33fbd..28fb5e0d71 100644
--- a/src/backend/parser/parse_agg.c
+++ b/src/backend/parser/parse_agg.c
@@ -575,6 +575,10 @@ check_agglevels_and_constraints(ParseState *pstate, Node *expr)
 			errkind = true;
 			break;
 
+		case EXPR_KIND_RPR_DEFINE:
+			errkind = true;
+			break;
+
 			/*
 			 * There is intentionally no default: case here, so that the
 			 * compiler will warn if we add a new ParseExprKind without
@@ -964,6 +968,9 @@ transformWindowFuncCall(ParseState *pstate, WindowFunc *wfunc,
 		case EXPR_KIND_CYCLE_MARK:
 			errkind = true;
 			break;
+		case EXPR_KIND_RPR_DEFINE:
+			errkind = true;
+			break;
 
 			/*
 			 * There is intentionally no default: case here, so that the
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index 334b9b42bd..c5d3c10683 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -100,7 +100,10 @@ static WindowClause *findWindowClause(List *wclist, const char *name);
 static Node *transformFrameOffset(ParseState *pstate, int frameOptions,
 								  Oid rangeopfamily, Oid rangeopcintype, Oid *inRangeFunc,
 								  Node *clause);
-
+static void transformRPR(ParseState *pstate, WindowClause *wc, WindowDef *windef, List **targetlist);
+static List *transformDefineClause(ParseState *pstate, WindowClause *wc, WindowDef *windef, List **targetlist);
+static void transformPatternClause(ParseState *pstate, WindowClause *wc, WindowDef *windef);
+static List *transformMeasureClause(ParseState *pstate, WindowClause *wc, WindowDef *windef);
 
 /*
  * transformFromClause -
@@ -2950,6 +2953,10 @@ transformWindowDefinitions(ParseState *pstate,
 											 rangeopfamily, rangeopcintype,
 											 &wc->endInRangeFunc,
 											 windef->endOffset);
+
+		/* Process Row Pattern Recognition related clauses */
+		transformRPR(pstate, wc, windef, targetlist);
+
 		wc->runCondition = NIL;
 		wc->winref = winref;
 
@@ -3815,3 +3822,272 @@ transformFrameOffset(ParseState *pstate, int frameOptions,
 
 	return node;
 }
+
+/*
+ * transformRPR
+ *		Process Row Pattern Recognition related clauses
+ */
+static void
+transformRPR(ParseState *pstate, WindowClause *wc, WindowDef *windef, List **targetlist)
+{
+	/*
+	 * Window definition exists?
+	 */
+	if (windef == NULL)
+		return;
+
+	/*
+	 * Row Pattern Common Syntax clause exists?
+	 */
+	if (windef->rpCommonSyntax == NULL)
+		return;
+
+	/* Check Frame option. Frame must start at current row */
+	if ((wc->frameOptions & FRAMEOPTION_START_CURRENT_ROW) == 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_SYNTAX_ERROR),
+				 errmsg("FRAME must start at current row when row patttern recognition is used")));
+
+	/* Transform AFTER MACH SKIP TO clause */
+	wc->rpSkipTo = windef->rpCommonSyntax->rpSkipTo;
+
+	/* Transform SEEK or INITIAL clause */
+	wc->initial = windef->rpCommonSyntax->initial;
+
+	/* Transform DEFINE clause into list of TargetEntry's */
+	wc->defineClause = transformDefineClause(pstate, wc, windef, targetlist);
+
+	/* Check PATTERN clause and copy to patternClause */
+	transformPatternClause(pstate, wc, windef);
+
+	/* Transform MEASURE clause */
+	transformMeasureClause(pstate, wc, windef);
+}
+
+/*
+ * transformDefineClause Process DEFINE clause and transform ResTarget into
+ *		list of TargetEntry.
+ *
+ * XXX we only support column reference in row pattern definition search
+ * condition, e.g. "price". <row pattern definition variable name>.<column
+ * reference> is not supported, e.g. "A.price".
+ */
+static List *
+transformDefineClause(ParseState *pstate, WindowClause *wc, WindowDef *windef, List **targetlist)
+{
+	/* DEFINE variable name initials */
+	static	char	*defineVariableInitials = "abcdefghijklmnopqrstuvwxyz";
+
+	ListCell		*lc, *l;
+	ResTarget		*restarget, *r;
+	List			*restargets;
+	List			*defineClause;
+	char			*name;
+	int				initialLen;
+	int				i;
+
+	/*
+	 * If Row Definition Common Syntax exists, DEFINE clause must exist.
+	 * (the raw parser should have already checked it.)
+	 */
+	Assert(windef->rpCommonSyntax->rpDefs != NULL);
+
+	/*
+	 * Check and add "A AS A IS TRUE" if pattern variable is missing in DEFINE
+	 * per the SQL standard.
+	 */
+	restargets = NIL;
+	foreach(lc, windef->rpCommonSyntax->rpPatterns)
+	{
+		A_Expr	*a;
+		bool	found = false;
+
+		if (!IsA(lfirst(lc), A_Expr))
+			ereport(ERROR,
+					errmsg("node type is not A_Expr"));
+
+		a = (A_Expr *)lfirst(lc);
+		name = strVal(a->lexpr);
+
+		foreach(l, windef->rpCommonSyntax->rpDefs)
+		{
+			restarget = (ResTarget *)lfirst(l);
+
+			if (!strcmp(restarget->name, name))
+			{
+				found = true;
+				break;
+			}
+		}
+
+		if (!found)
+		{
+			/*
+			 * "name" is missing. So create "name AS name IS TRUE" ResTarget
+			 * node and add it to the temporary list.
+			 */
+			A_Const	   *n;
+
+			restarget = makeNode(ResTarget);
+			n = makeNode(A_Const);
+			n->val.boolval.type = T_Boolean;
+			n->val.boolval.boolval = true;
+			n->location = -1;
+			restarget->name = pstrdup(name);
+			restarget->indirection = NIL;
+			restarget->val = (Node *)n;
+			restarget->location = -1;
+			restargets = lappend((List *)restargets, restarget);
+		}
+	}
+
+	if (list_length(restargets) >= 1)
+	{
+		/* add missing DEFINEs */
+		windef->rpCommonSyntax->rpDefs = list_concat(windef->rpCommonSyntax->rpDefs,
+													 restargets);
+		list_free(restargets);
+	}
+
+	/*
+	 * Check for duplicate row pattern definition variables.  The standard
+	 * requires that no two row pattern definition variable names shall be
+	 * equivalent.
+	 */
+	restargets = NIL;
+	foreach(lc, windef->rpCommonSyntax->rpDefs)
+	{
+		restarget = (ResTarget *)lfirst(lc);
+		name = restarget->name;
+
+		/*
+		 * Add DEFINE expression (Restarget->val) to the targetlist as a
+		 * TargetEntry if it does not exist yet. Planner will add the column
+		 * ref var node to the outer plan's target list later on. This makes
+		 * DEFINE expression could access the outer tuple while evaluating
+		 * PATTERN.
+		 *
+		 * XXX: adding whole expressions of DEFINE to the plan.targetlist is
+		 * not so good, because it's not necessary to evalute the expression
+		 * in the target list while running the plan. We should extract the
+		 * var nodes only then add them to the plan.targetlist.
+		 */
+		findTargetlistEntrySQL99(pstate, (Node *)restarget->val, targetlist, EXPR_KIND_RPR_DEFINE);
+
+		/*
+		 * Make sure that the row pattern definition search condition is a
+		 * boolean expression.
+		 */
+		transformWhereClause(pstate, restarget->val,
+							 EXPR_KIND_RPR_DEFINE, "DEFINE");
+
+		foreach(l, restargets)
+		{
+			char		*n;
+
+			r = (ResTarget *) lfirst(l);
+			n = r->name;
+
+			if (!strcmp(n, name))
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("row pattern definition variable name \"%s\" appears more than once in DEFINE clause",
+								name),
+						 parser_errposition(pstate, exprLocation((Node *)r))));
+		}
+		restargets = lappend(restargets, restarget);
+	}
+	list_free(restargets);
+
+	/*
+	 * Create list of row pattern DEFINE variable name's initial.
+	 * We assign [a-z] to them (up to 26 variable names are allowed).
+	 */
+	restargets = NIL;
+	i = 0;
+	initialLen = strlen(defineVariableInitials);
+
+	foreach(lc, windef->rpCommonSyntax->rpDefs)
+	{
+		char	initial[2];
+
+		restarget = (ResTarget *)lfirst(lc);
+		name = restarget->name;
+
+		if (i >= initialLen)
+		{
+			ereport(ERROR,
+					(errcode(ERRCODE_SYNTAX_ERROR),
+					 errmsg("number of row pattern definition variable names exceeds %d", initialLen),
+					 parser_errposition(pstate, exprLocation((Node *)restarget))));
+		}
+		initial[0] = defineVariableInitials[i++];
+		initial[1] = '\0';
+		wc->defineInitial = lappend(wc->defineInitial, makeString(pstrdup(initial)));
+	}
+
+	defineClause = transformTargetList(pstate, windef->rpCommonSyntax->rpDefs,
+							   EXPR_KIND_RPR_DEFINE);
+
+	/* mark column origins */
+	markTargetListOrigins(pstate, defineClause);
+
+	/* mark all nodes in the DEFINE clause tree with collation information */
+	assign_expr_collations(pstate, (Node *)defineClause);
+
+	return defineClause;
+}
+
+/*
+ * transformPatternClause
+ *		Process PATTERN clause and return PATTERN clause in the raw parse tree
+ */
+static void
+transformPatternClause(ParseState *pstate, WindowClause *wc, WindowDef *windef)
+{
+	ListCell	*lc;
+
+	/*
+	 * Row Pattern Common Syntax clause exists?
+	 */
+	if (windef->rpCommonSyntax == NULL)
+		return;
+
+	wc->patternVariable = NIL;
+	wc->patternRegexp = NIL;
+	foreach(lc, windef->rpCommonSyntax->rpPatterns)
+	{
+		A_Expr	*a;
+		char	*name;
+		char	*regexp;
+
+		if (!IsA(lfirst(lc), A_Expr))
+			ereport(ERROR,
+					errmsg("node type is not A_Expr"));
+
+		a = (A_Expr *)lfirst(lc);
+		name = strVal(a->lexpr);
+
+		wc->patternVariable = lappend(wc->patternVariable, makeString(pstrdup(name)));
+		regexp = strVal(lfirst(list_head(a->name)));
+		wc->patternRegexp = lappend(wc->patternRegexp, makeString(pstrdup(regexp)));
+	}
+}
+
+/*
+ * transformMeasureClause
+ *		Process MEASURE clause
+ *	XXX MEASURE clause is not supported yet
+ */
+static List *
+transformMeasureClause(ParseState *pstate, WindowClause *wc, WindowDef *windef)
+{
+	if (windef->rowPatternMeasures == NIL)
+		return NIL;
+
+	ereport(ERROR,
+			(errcode(ERRCODE_SYNTAX_ERROR),
+			 errmsg("%s","MEASURE clause is not supported yet"),
+			 parser_errposition(pstate, exprLocation((Node *)windef->rowPatternMeasures))));
+	return NIL;
+}
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 64c582c344..18b58ac263 100644
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -557,6 +557,7 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref)
 		case EXPR_KIND_COPY_WHERE:
 		case EXPR_KIND_GENERATED_COLUMN:
 		case EXPR_KIND_CYCLE_MARK:
+		case EXPR_KIND_RPR_DEFINE:
 			/* okay */
 			break;
 
@@ -1770,6 +1771,7 @@ transformSubLink(ParseState *pstate, SubLink *sublink)
 		case EXPR_KIND_VALUES:
 		case EXPR_KIND_VALUES_SINGLE:
 		case EXPR_KIND_CYCLE_MARK:
+		case EXPR_KIND_RPR_DEFINE:
 			/* okay */
 			break;
 		case EXPR_KIND_CHECK_CONSTRAINT:
@@ -3149,6 +3151,8 @@ ParseExprKindName(ParseExprKind exprKind)
 			return "GENERATED AS";
 		case EXPR_KIND_CYCLE_MARK:
 			return "CYCLE";
+		case EXPR_KIND_RPR_DEFINE:
+			return "DEFINE";
 
 			/*
 			 * There is intentionally no default: case here, so that the
diff --git a/src/backend/parser/parse_func.c b/src/backend/parser/parse_func.c
index 6c29471bb3..086431f91b 100644
--- a/src/backend/parser/parse_func.c
+++ b/src/backend/parser/parse_func.c
@@ -2656,6 +2656,9 @@ check_srf_call_placement(ParseState *pstate, Node *last_srf, int location)
 		case EXPR_KIND_CYCLE_MARK:
 			errkind = true;
 			break;
+		case EXPR_KIND_RPR_DEFINE:
+			errkind = true;
+			break;
 
 			/*
 			 * There is intentionally no default: case here, so that the
-- 
2.25.1


----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v11-0003-Row-pattern-recognition-patch-planner.patch"



^ permalink  raw  reply  [nested|flat] 5+ messages in thread

* Re: POC: track vacuum/analyze cumulative time per relation
@ 2025-01-10 14:37  Alena Rybakina <[email protected]>
  0 siblings, 1 reply; 5+ messages in thread

From: Alena Rybakina @ 2025-01-10 14:37 UTC (permalink / raw)
  To: wenhui qiu <[email protected]>; Sami Imseih <[email protected]>; +Cc: pgsql-hackers

Hi!

On 04.01.2025 06:41, wenhui qiu wrote:
> Hi Sami
>  Thank you for your path,it seems some path monitor vacuum status,Can 
> we synthesize their good ideas together。
>
I've been working on a patch that collects vacuum statistics since May 
[0]. It includes heap and index relation vacuum statistics, and of 
course, database vacuum statistics. We welcome reviews and any feedback!

It collects a bit more information than total_time, such as delay_time, 
buffer statistics, wal statistics, number of processed, skipped pages 
and tuples during vacuum operations, so
this information gives a complete picture of vacuum efficiency, because 
analyzing only total_time statistics does not give a complete picture of 
what vacuum did: was it cleaning almost huge index, cleaning tables or 
just sleeping.

[0] https://commitfest.postgresql.org/51/5012/

-- 
Regards,
Alena Rybakina
Postgres Professional







^ permalink  raw  reply  [nested|flat] 5+ messages in thread

* Re: POC: track vacuum/analyze cumulative time per relation
@ 2025-01-10 16:07  Sami Imseih <[email protected]>
  parent: Alena Rybakina <[email protected]>
  0 siblings, 1 reply; 5+ messages in thread

From: Sami Imseih @ 2025-01-10 16:07 UTC (permalink / raw)
  To: Alena Rybakina <[email protected]>; +Cc: wenhui qiu <[email protected]>; pgsql-hackers

> this information gives a complete picture of vacuum efficiency, because
> analyzing only total_time statistics does not give a complete picture of
> what vacuum did: was it cleaning almost huge index, cleaning tables or
> just sleeping.

The purpose of total_time is to be able to calculate the average
time of a vacuum per relation from pg_stat_all_tables (by
total_time/vacuum_count) This is useful on its own to be able to
trend slow downs of vacuum ( or improvements after vacuum tuning )
for specific relations.

The work going into [1] is more detailed and will be useful
for deep dive investigations.In short, I think both proposals
have merit.

[1] https://commitfest.postgresql.org/51/5012/

Regards,

Sami






^ permalink  raw  reply  [nested|flat] 5+ messages in thread

* Re: POC: track vacuum/analyze cumulative time per relation
@ 2025-01-10 16:21  Sami Imseih <[email protected]>
  parent: Sami Imseih <[email protected]>
  0 siblings, 0 replies; 5+ messages in thread

From: Sami Imseih @ 2025-01-10 16:21 UTC (permalink / raw)
  To: Alena Rybakina <[email protected]>; +Cc: wenhui qiu <[email protected]>; pgsql-hackers

> > this information gives a complete picture of vacuum efficiency, because
> > analyzing only total_time statistics does not give a complete picture of
> > what vacuum did: was it cleaning almost huge index, cleaning tables or
> > just sleeping.
>
> The purpose of total_time is to be able to calculate the average
> time of a vacuum per relation from pg_stat_all_tables (by
> total_time/vacuum_count) This is useful on its own to be able to
> trend slow downs of vacuum ( or improvements after vacuum tuning )
> for specific relations.
>
> The work going into [1] is more detailed and will be useful
> for deep dive investigations.In short, I think both proposals
> have merit.

Missed this point in my last reply. This patch also tracks
(auto)analyze per relation cumulative timing which can
be useful along with (auto)analyze_count to derive
the average.

Regards,

Sami






^ permalink  raw  reply  [nested|flat] 5+ messages in thread


end of thread, other threads:[~2025-01-10 16:21 UTC | newest]

Thread overview: 5+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2018-10-11 01:03 [PATCH 2/4] Write WAL for empty nbtree index build Kyotaro Horiguchi <[email protected]>
2023-11-08 06:57 [PATCH v11 2/7] Row pattern recognition patch (parse/analysis). Tatsuo Ishii <[email protected]>
2025-01-10 14:37 Re: POC: track vacuum/analyze cumulative time per relation Alena Rybakina <[email protected]>
2025-01-10 16:07 ` Re: POC: track vacuum/analyze cumulative time per relation Sami Imseih <[email protected]>
2025-01-10 16:21   ` Re: POC: track vacuum/analyze cumulative time per relation Sami Imseih <[email protected]>

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