Move responsibility for setting QuerySnapshot for utility statements

into postgres.c; make sure it happens for all cases that seem to need it.
Perhaps it would be better to explicitly exclude just a few utility
statement types from setting a snapshot?
This commit is contained in:
Tom Lane 2002-10-08 17:17:19 +00:00
parent 5fc32fbf87
commit 56ece37384
3 changed files with 35 additions and 20 deletions

View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.298 2002/10/06 03:56:03 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.299 2002/10/08 17:17:19 tgl Exp $
*
* NOTES
* this is the "main" module of the postgres backend and
@ -716,20 +716,33 @@ pg_exec_query_string(StringInfo query_string, /* string to execute */
/*
* process utility functions (create, destroy, etc..)
*/
Node *utilityStmt = querytree->utilityStmt;
elog(DEBUG2, "ProcessUtility");
/* set snapshot if utility stmt needs one */
/* XXX maybe cleaner to list those that shouldn't set one? */
if (IsA(utilityStmt, AlterTableStmt) ||
IsA(utilityStmt, ClusterStmt) ||
IsA(utilityStmt, CopyStmt) ||
IsA(utilityStmt, ExecuteStmt) ||
IsA(utilityStmt, ExplainStmt) ||
IsA(utilityStmt, IndexStmt) ||
IsA(utilityStmt, PrepareStmt) ||
IsA(utilityStmt, ReindexStmt))
SetQuerySnapshot();
if (querytree->originalQuery)
{
/* utility statement can override default tag string */
ProcessUtility(querytree->utilityStmt, dest,
completionTag);
ProcessUtility(utilityStmt, dest, completionTag);
if (completionTag[0])
commandTag = completionTag;
}
else
{
/* utility added by rewrite cannot override tag */
ProcessUtility(querytree->utilityStmt, dest, NULL);
ProcessUtility(utilityStmt, dest, NULL);
}
}
else
@ -739,14 +752,20 @@ pg_exec_query_string(StringInfo query_string, /* string to execute */
*/
Plan *plan;
/*
* Initialize snapshot state for query. This has to
* be done before running the planner, because it might
* try to evaluate immutable or stable functions, which
* in turn might run queries.
*/
SetQuerySnapshot();
/* Make the plan */
plan = pg_plan_query(querytree);
/* if we got a cancel signal whilst planning, quit */
CHECK_FOR_INTERRUPTS();
/* Initialize snapshot state for query */
SetQuerySnapshot();
/*
* execute the plan
*/
@ -1701,7 +1720,7 @@ PostgresMain(int argc, char *argv[], const char *username)
if (!IsUnderPostmaster)
{
puts("\nPOSTGRES backend interactive interface ");
puts("$Revision: 1.298 $ $Date: 2002/10/06 03:56:03 $\n");
puts("$Revision: 1.299 $ $Date: 2002/10/08 17:17:19 $\n");
}
/*
@ -1886,6 +1905,9 @@ PostgresMain(int argc, char *argv[], const char *username)
/* start an xact for this function invocation */
start_xact_command();
/* assume it may need a snapshot */
SetQuerySnapshot();
if (HandleFunctionRequest() == EOF)
{
/* lost frontend connection during F message input */

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@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.178 2002/09/26 22:58:33 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.179 2002/10/08 17:17:19 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -380,14 +380,7 @@ ProcessUtility(Node *parsetree,
break;
case T_CopyStmt:
{
CopyStmt *stmt = (CopyStmt *) parsetree;
if (!stmt->is_from)
SetQuerySnapshot();
DoCopy(stmt);
}
DoCopy((CopyStmt *) parsetree);
break;
case T_PrepareStmt:

View File

@ -16,7 +16,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/time/tqual.c,v 1.60 2002/09/04 20:31:33 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/time/tqual.c,v 1.61 2002/10/08 17:17:19 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -977,8 +977,8 @@ CopyQuerySnapshot(void)
{
Snapshot snapshot;
if (QuerySnapshot == NULL) /* should be set already, but... */
SetQuerySnapshot();
if (QuerySnapshot == NULL) /* should be set beforehand */
elog(ERROR, "CopyQuerySnapshot: no snapshot has been set");
snapshot = (Snapshot) palloc(sizeof(SnapshotData));
memcpy(snapshot, QuerySnapshot, sizeof(SnapshotData));