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-rw-r--r--src/backend/commands/trigger.c52
-rw-r--r--src/backend/parser/analyze.c48
-rw-r--r--src/backend/tcop/postgres.c54
-rw-r--r--src/include/parser/analyze.h3
4 files changed, 142 insertions, 15 deletions
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 0bc6f10cc79..627be4d5813 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.210.2.6 2008/10/25 03:32:51 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.210.2.7 2008/12/13 02:00:52 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -3181,19 +3181,51 @@ AfterTriggerSetState(ConstraintsSetStmt *stmt)
if (!stmt->deferred)
{
AfterTriggerEventList *events = &afterTriggers->events;
+ Snapshot saveActiveSnapshot = ActiveSnapshot;
- while (afterTriggerMarkEvents(events, NULL, true))
+ /* PG_TRY to ensure previous ActiveSnapshot is restored on error */
+ PG_TRY();
{
- CommandId firing_id = afterTriggers->firing_counter++;
+ Snapshot mySnapshot = NULL;
- /*
- * We can delete fired events if we are at top transaction level,
- * but we'd better not if inside a subtransaction, since the
- * subtransaction could later get rolled back.
- */
- afterTriggerInvokeEvents(-1, firing_id, NULL,
- !IsSubTransaction());
+ while (afterTriggerMarkEvents(events, NULL, true))
+ {
+ CommandId firing_id = afterTriggers->firing_counter++;
+
+ /*
+ * Make sure a snapshot has been established in case trigger
+ * functions need one. Note that we avoid setting a snapshot
+ * if we don't find at least one trigger that has to be fired
+ * now. This is so that BEGIN; SET CONSTRAINTS ...; SET
+ * TRANSACTION ISOLATION LEVEL SERIALIZABLE; ... works
+ * properly. (If we are at the start of a transaction it's
+ * not possible for any trigger events to be queued yet.)
+ */
+ if (mySnapshot == NULL)
+ {
+ mySnapshot = CopySnapshot(GetTransactionSnapshot());
+ ActiveSnapshot = mySnapshot;
+ }
+
+ /*
+ * We can delete fired events if we are at top transaction level,
+ * but we'd better not if inside a subtransaction, since the
+ * subtransaction could later get rolled back.
+ */
+ afterTriggerInvokeEvents(-1, firing_id, NULL,
+ !IsSubTransaction());
+ }
+
+ if (mySnapshot)
+ FreeSnapshot(mySnapshot);
+ }
+ PG_CATCH();
+ {
+ ActiveSnapshot = saveActiveSnapshot;
+ PG_RE_THROW();
}
+ PG_END_TRY();
+ ActiveSnapshot = saveActiveSnapshot;
}
}
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index e1be8a89467..226f7c76339 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.353.2.1 2007/06/20 18:21:08 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.353.2.2 2008/12/13 02:00:52 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -432,6 +432,52 @@ transformStmt(ParseState *pstate, Node *parseTree,
return result;
}
+/*
+ * analyze_requires_snapshot
+ * Returns true if a snapshot must be set before doing parse analysis
+ * on the given raw parse tree.
+ *
+ * Classification here should match transformStmt().
+ */
+bool
+analyze_requires_snapshot(Node *parseTree)
+{
+ bool result;
+
+ switch (nodeTag(parseTree))
+ {
+ /*
+ * Optimizable statements
+ */
+ case T_InsertStmt:
+ case T_DeleteStmt:
+ case T_UpdateStmt:
+ case T_SelectStmt:
+ result = true;
+ break;
+
+ /*
+ * Special cases
+ */
+ case T_DeclareCursorStmt:
+ /* yes, because it's analyzed just like SELECT */
+ result = true;
+ break;
+
+ case T_ExplainStmt:
+ /* yes, because it's analyzed just like SELECT */
+ result = true;
+ break;
+
+ default:
+ /* other utility statements don't have any active parse analysis */
+ result = false;
+ break;
+ }
+
+ return result;
+}
+
static Query *
transformViewStmt(ParseState *pstate, ViewStmt *stmt,
List **extras_before, List **extras_after)
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index bcb116a50e4..1ebcaa482b6 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/tcop/postgres.c,v 1.518.2.1 2007/01/04 00:58:01 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/tcop/postgres.c,v 1.518.2.2 2008/12/13 02:00:52 tgl Exp $
*
* NOTES
* this is the "main" module of the postgres backend and
@@ -655,6 +655,9 @@ pg_plan_query(Query *querytree, ParamListInfo boundParams)
if (querytree->commandType == CMD_UTILITY)
return NULL;
+ /* Planner must have a snapshot in case it calls user-defined functions. */
+ Assert(ActiveSnapshot != NULL);
+
if (log_planner_stats)
ResetUsage();
@@ -823,6 +826,7 @@ exec_simple_query(const char *query_string)
foreach(parsetree_item, parsetree_list)
{
Node *parsetree = (Node *) lfirst(parsetree_item);
+ Snapshot mySnapshot = NULL;
const char *commandTag;
char completionTag[COMPLETION_TAG_BUFSIZE];
List *querytree_list,
@@ -865,6 +869,15 @@ exec_simple_query(const char *query_string)
CHECK_FOR_INTERRUPTS();
/*
+ * Set up a snapshot if parse analysis/planning will need one.
+ */
+ if (analyze_requires_snapshot(parsetree))
+ {
+ mySnapshot = CopySnapshot(GetTransactionSnapshot());
+ ActiveSnapshot = mySnapshot;
+ }
+
+ /*
* OK to analyze, rewrite, and plan this query.
*
* Switch to appropriate context for constructing querytrees (again,
@@ -875,7 +888,12 @@ exec_simple_query(const char *query_string)
querytree_list = pg_analyze_and_rewrite(parsetree, query_string,
NULL, 0);
- plantree_list = pg_plan_queries(querytree_list, NULL, true);
+ plantree_list = pg_plan_queries(querytree_list, NULL, false);
+
+ /* Done with the snapshot used for parsing/planning */
+ ActiveSnapshot = NULL;
+ if (mySnapshot)
+ FreeSnapshot(mySnapshot);
/* If we got a cancel signal in analysis or planning, quit */
CHECK_FOR_INTERRUPTS();
@@ -1127,6 +1145,7 @@ exec_parse_message(const char *query_string, /* string to execute */
if (parsetree_list != NIL)
{
Node *parsetree = (Node *) linitial(parsetree_list);
+ Snapshot mySnapshot = NULL;
int i;
/*
@@ -1150,6 +1169,15 @@ exec_parse_message(const char *query_string, /* string to execute */
"commands ignored until end of transaction block")));
/*
+ * Set up a snapshot if parse analysis/planning will need one.
+ */
+ if (analyze_requires_snapshot(parsetree))
+ {
+ mySnapshot = CopySnapshot(GetTransactionSnapshot());
+ ActiveSnapshot = mySnapshot;
+ }
+
+ /*
* OK to analyze, rewrite, and plan this query. Note that the
* originally specified parameter set is not required to be complete,
* so we have to use parse_analyze_varparams().
@@ -1191,7 +1219,12 @@ exec_parse_message(const char *query_string, /* string to execute */
if (!is_named && numParams > 0)
plantree_list = NIL;
else
- plantree_list = pg_plan_queries(querytree_list, NULL, true);
+ plantree_list = pg_plan_queries(querytree_list, NULL, false);
+
+ /* Done with the snapshot used for parsing/planning */
+ ActiveSnapshot = NULL;
+ if (mySnapshot)
+ FreeSnapshot(mySnapshot);
}
else
{
@@ -1401,10 +1434,18 @@ exec_bind_message(StringInfo input_message)
*/
if (numParams > 0)
{
+ Snapshot mySnapshot;
ListCell *l;
MemoryContext oldContext;
int paramno;
+ /*
+ * Set a snapshot if we have parameters to fetch (since the input
+ * functions might need it).
+ */
+ mySnapshot = CopySnapshot(GetTransactionSnapshot());
+ ActiveSnapshot = mySnapshot;
+
oldContext = MemoryContextSwitchTo(PortalGetHeapMemory(portal));
/* sizeof(ParamListInfoData) includes the first array element */
@@ -1536,6 +1577,10 @@ exec_bind_message(StringInfo input_message)
}
MemoryContextSwitchTo(oldContext);
+
+ /* Done with the snapshot used for parameter I/O */
+ ActiveSnapshot = NULL;
+ FreeSnapshot(mySnapshot);
}
else
params = NULL;
@@ -3285,6 +3330,9 @@ PostgresMain(int argc, char *argv[], const char *username)
*/
debug_query_string = NULL;
+ /* No active snapshot any more either */
+ ActiveSnapshot = NULL;
+
/*
* Abort the current transaction in order to recover.
*/
diff --git a/src/include/parser/analyze.h b/src/include/parser/analyze.h
index 7866472f79e..c90517d305d 100644
--- a/src/include/parser/analyze.h
+++ b/src/include/parser/analyze.h
@@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/parser/analyze.h,v 1.34 2006/10/04 00:30:09 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/parser/analyze.h,v 1.34.2.1 2008/12/13 02:00:53 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -21,6 +21,7 @@ extern List *parse_analyze(Node *parseTree, const char *sourceText,
extern List *parse_analyze_varparams(Node *parseTree, const char *sourceText,
Oid **paramTypes, int *numParams);
extern List *parse_sub_analyze(Node *parseTree, ParseState *parentParseState);
+extern bool analyze_requires_snapshot(Node *parseTree);
extern List *analyzeCreateSchemaStmt(CreateSchemaStmt *stmt);
extern void CheckSelectLocking(Query *qry);
extern void applyLockingClause(Query *qry, Index rtindex,
generated by cgit v1.2.3 (git 2.25.1) at 2025-08-05 07:07:00 +0000