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Fix failure to ensure that a snapshot is available to datatype input functions

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when they are invoked by the parser.  We had been setting up a snapshot at
plan time but really it needs to be done earlier, before parse analysis.
Per report from Dmitry Koterov.

Also fix two related problems discovered while poking at this one:
exec_bind_message called datatype input functions without establishing a
snapshot, and SET CONSTRAINTS IMMEDIATE could call trigger functions without
establishing a snapshot.

Backpatch to 8.2.  The underlying problem goes much further back, but it is
masked in 8.1 and before because we didn't attempt to invoke domain check
constraints within datatype input.  It would only be exposed if a C-language
datatype input function used the snapshot; which evidently none do, or we'd
have heard complaints sooner.  Since this code has changed a lot over time,
a back-patch is hardly risk-free, and so I'm disinclined to patch further
than absolutely necessary.
This commit is contained in:
Tom Lane
2008-12-13 02:00:53 +00:00
parent 4914b70847
commit 7ae3c0f67b
4 changed files with 142 additions and 15 deletions
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54
src/backend/tcop/postgres.c
View File

@@ -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,
@@ -864,6 +868,15 @@ exec_simple_query(const char *query_string)
/* If we got a cancel signal in parsing or prior command, quit */
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.
*
@@ -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;
/*
@@ -1149,6 +1168,15 @@ exec_parse_message(const char *query_string, /* string to execute */
errmsg("current transaction is aborted, "
"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,
@@ -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.
*/