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help / color / mirror / Atom feedFrom: Álvaro Herrera <[email protected]>
Subject: [PATCH v4] Restructure CreateStatsStmt parse-analysis processing
Date: Fri, 17 Oct 2025 13:55:15 +0200
Previously, a lot of code would be run in the ProcessUtility pipeline,
where it is not welcome (that's supposed to be just a giant dispatcher
switch). Move the parse analysis code to CreateStatistics() instead,
which then means we don't need to open the relation twice; it also
allows us to give a better error message when something other than a
relation name is given in the FROM clause. It also means we no longer
need to do the transform step in ATPostAlterTypeParse(), which saves a
bit of code.
Author: Jian He <[email protected]>
Discussion: https://postgr.es/m/CACJufxFcvo=fM6J9RC88n1U=eS9+5QdftwUNQMu5h7OgjmqDwQ@mail.gmail.com
---
src/backend/commands/statscmds.c | 13 +++++++++++--
src/backend/commands/tablecmds.c | 16 +---------------
src/backend/parser/parse_utilcmd.c | 13 +++----------
src/backend/tcop/utility.c | 29 +----------------------------
src/include/commands/defrem.h | 2 +-
src/include/parser/parse_utilcmd.h | 2 +-
6 files changed, 18 insertions(+), 57 deletions(-)
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 27bf67e7c4b..632228c13ed 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -30,6 +30,7 @@
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/optimizer.h"
+#include "parser/parse_utilcmd.h"
#include "statistics/statistics.h"
#include "utils/acl.h"
#include "utils/builtins.h"
@@ -58,9 +59,14 @@ compare_int16(const void *a, const void *b)
/*
* CREATE STATISTICS
+ *
+ * queryString is the source text of the CREATE STATISTICS command, if any.
+ *
+ * Normally stmt has not already undergone transformation, but in some cases
+ * it might have, such as CREATE TABLE (LIKE).
*/
ObjectAddress
-CreateStatistics(CreateStatsStmt *stmt)
+CreateStatistics(CreateStatsStmt *stmt, const char *queryString)
{
int16 attnums[STATS_MAX_DIMENSIONS];
int nattnums = 0;
@@ -113,7 +119,7 @@ CreateStatistics(CreateStatsStmt *stmt)
if (!IsA(rln, RangeVar))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("only a single relation is allowed in CREATE STATISTICS")));
+ errmsg("CREATE STATISTICS only supports relation names in the FROM clause")));
/*
* CREATE STATISTICS will influence future execution plans but does
@@ -151,6 +157,9 @@ CreateStatistics(CreateStatsStmt *stmt)
Assert(rel);
relid = RelationGetRelid(rel);
+ /* Run parse analysis */
+ stmt = transformStatsStmt(rel, stmt, queryString);
+
/*
* If the node has a name, split it up and determine creation namespace.
* If not, put the object in the same namespace as the relation, and cons
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 5fd8b51312c..a1732b71e55 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -9650,16 +9650,7 @@ static ObjectAddress
ATExecAddStatistics(AlteredTableInfo *tab, Relation rel,
CreateStatsStmt *stmt, bool is_rebuild, LOCKMODE lockmode)
{
- ObjectAddress address;
-
- Assert(IsA(stmt, CreateStatsStmt));
-
- /* The CreateStatsStmt has already been through transformStatsStmt */
- Assert(stmt->transformed);
-
- address = CreateStatistics(stmt);
-
- return address;
+ return CreateStatistics(stmt, NULL);
}
/*
@@ -15632,11 +15623,6 @@ ATPostAlterTypeParse(Oid oldId, Oid oldRelId, Oid refRelId, char *cmd,
querytree_list = lappend(querytree_list, stmt);
querytree_list = list_concat(querytree_list, afterStmts);
}
- else if (IsA(stmt, CreateStatsStmt))
- querytree_list = lappend(querytree_list,
- transformStatsStmt(oldRelId,
- (CreateStatsStmt *) stmt,
- cmd));
else
querytree_list = lappend(querytree_list, stmt);
}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index e96b38a59d5..89c8315117b 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -3137,16 +3137,14 @@ transformIndexStmt(Oid relid, IndexStmt *stmt, const char *queryString)
* transformStatsStmt - parse analysis for CREATE STATISTICS
*
* To avoid race conditions, it's important that this function relies only on
- * the passed-in relid (and not on stmt->relation) to determine the target
- * relation.
+ * the passed-in rel (and not on stmt->relation) as the target relation.
*/
CreateStatsStmt *
-transformStatsStmt(Oid relid, CreateStatsStmt *stmt, const char *queryString)
+transformStatsStmt(Relation rel, CreateStatsStmt *stmt, const char *queryString)
{
ParseState *pstate;
ParseNamespaceItem *nsitem;
ListCell *l;
- Relation rel;
/* Nothing to do if statement already transformed. */
if (stmt->transformed)
@@ -3158,10 +3156,8 @@ transformStatsStmt(Oid relid, CreateStatsStmt *stmt, const char *queryString)
/*
* Put the parent table into the rtable so that the expressions can refer
- * to its fields without qualification. Caller is responsible for locking
- * relation, but we still need to open it.
+ * to its fields without qualification.
*/
- rel = relation_open(relid, NoLock);
nsitem = addRangeTableEntryForRelation(pstate, rel,
AccessShareLock,
NULL, false, true);
@@ -3196,9 +3192,6 @@ transformStatsStmt(Oid relid, CreateStatsStmt *stmt, const char *queryString)
free_parsestate(pstate);
- /* Close relation */
- table_close(rel, NoLock);
-
/* Mark statement as successfully transformed */
stmt->transformed = true;
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 918db53dd5e..027356f6e77 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -1866,34 +1866,7 @@ ProcessUtilitySlow(ParseState *pstate,
break;
case T_CreateStatsStmt:
- {
- Oid relid;
- CreateStatsStmt *stmt = (CreateStatsStmt *) parsetree;
- RangeVar *rel = (RangeVar *) linitial(stmt->relations);
-
- if (!IsA(rel, RangeVar))
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("CREATE STATISTICS only supports relation names in the FROM clause")));
-
- /*
- * CREATE STATISTICS will influence future execution plans
- * but does not interfere with currently executing plans.
- * So it should be enough to take ShareUpdateExclusiveLock
- * on relation, conflicting with ANALYZE and other DDL
- * that sets statistical information, but not with normal
- * queries.
- *
- * XXX RangeVarCallbackOwnsRelation not needed here, to
- * keep the same behavior as before.
- */
- relid = RangeVarGetRelid(rel, ShareUpdateExclusiveLock, false);
-
- /* Run parse analysis ... */
- stmt = transformStatsStmt(relid, stmt, queryString);
-
- address = CreateStatistics(stmt);
- }
+ address = CreateStatistics((CreateStatsStmt *) parsetree, queryString);
break;
case T_AlterStatsStmt:
diff --git a/src/include/commands/defrem.h b/src/include/commands/defrem.h
index dd22b5efdfd..684f62109fd 100644
--- a/src/include/commands/defrem.h
+++ b/src/include/commands/defrem.h
@@ -85,7 +85,7 @@ extern void RemoveOperatorById(Oid operOid);
extern ObjectAddress AlterOperator(AlterOperatorStmt *stmt);
/* commands/statscmds.c */
-extern ObjectAddress CreateStatistics(CreateStatsStmt *stmt);
+extern ObjectAddress CreateStatistics(CreateStatsStmt *stmt, const char *queryString);
extern ObjectAddress AlterStatistics(AlterStatsStmt *stmt);
extern void RemoveStatisticsById(Oid statsOid);
extern void RemoveStatisticsDataById(Oid statsOid, bool inh);
diff --git a/src/include/parser/parse_utilcmd.h b/src/include/parser/parse_utilcmd.h
index 4965fac4495..67255799f0a 100644
--- a/src/include/parser/parse_utilcmd.h
+++ b/src/include/parser/parse_utilcmd.h
@@ -26,7 +26,7 @@ extern AlterTableStmt *transformAlterTableStmt(Oid relid, AlterTableStmt *stmt,
List **afterStmts);
extern IndexStmt *transformIndexStmt(Oid relid, IndexStmt *stmt,
const char *queryString);
-extern CreateStatsStmt *transformStatsStmt(Oid relid, CreateStatsStmt *stmt,
+extern CreateStatsStmt *transformStatsStmt(Relation rel, CreateStatsStmt *stmt,
const char *queryString);
extern void transformRuleStmt(RuleStmt *stmt, const char *queryString,
List **actions, Node **whereClause);
--
2.47.3
--xzcma6eafn4gmiua--
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