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Repair RI trigger visibility problems (this time for sure ;-)) per recent

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discussion on pgsql-hackers: in READ COMMITTED mode we just have to force
a QuerySnapshot update in the trigger, but in SERIALIZABLE mode we have
to run the scan under a current snapshot and then complain if any rows
would be updated/deleted that are not visible in the transaction snapshot.
This commit is contained in:
Tom Lane
2003-10-01 21:30:53 +00:00
parent 6099bc03f3
commit 55d85f42a8
15 changed files with 210 additions and 84 deletions
Download Patch File Download Diff File Expand all files Collapse all files

55
src/backend/utils/adt/ri_triggers.c
View File

@@ -17,7 +17,7 @@
*
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
*
* $Header: /cvsroot/pgsql/src/backend/utils/adt/ri_triggers.c,v 1.60 2003/09/29 00:05:25 petere Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/adt/ri_triggers.c,v 1.61 2003/10/01 21:30:52 tgl Exp $
*
* ----------
*/
@@ -157,6 +157,7 @@ static void *ri_PlanCheck(const char *querystr, int nargs, Oid *argtypes,
static bool ri_PerformCheck(RI_QueryKey *qkey, void *qplan,
Relation fk_rel, Relation pk_rel,
HeapTuple old_tuple, HeapTuple new_tuple,
bool detectNewRows,
int expect_OK, const char *constrname);
static void ri_ExtractValues(RI_QueryKey *qkey, int key_idx,
Relation rel, HeapTuple tuple,
@@ -276,6 +277,7 @@ RI_FKey_check(PG_FUNCTION_ARGS)
ri_PerformCheck(&qkey, qplan,
fk_rel, pk_rel,
NULL, NULL,
false,
SPI_OK_SELECT,
tgargs[RI_CONSTRAINT_NAME_ARGNO]);
@@ -433,6 +435,7 @@ RI_FKey_check(PG_FUNCTION_ARGS)
ri_PerformCheck(&qkey, qplan,
fk_rel, pk_rel,
NULL, new_row,
false,
SPI_OK_SELECT,
tgargs[RI_CONSTRAINT_NAME_ARGNO]);
@@ -594,6 +597,7 @@ ri_Check_Pk_Match(Relation pk_rel, Relation fk_rel,
result = ri_PerformCheck(&qkey, qplan,
fk_rel, pk_rel,
old_row, NULL,
true, /* treat like update */
SPI_OK_SELECT, NULL);
if (SPI_finish() != SPI_OK_FINISH)
@@ -752,6 +756,7 @@ RI_FKey_noaction_del(PG_FUNCTION_ARGS)
ri_PerformCheck(&qkey, qplan,
fk_rel, pk_rel,
old_row, NULL,
true, /* must detect new rows */
SPI_OK_SELECT,
tgargs[RI_CONSTRAINT_NAME_ARGNO]);
@@ -942,6 +947,7 @@ RI_FKey_noaction_upd(PG_FUNCTION_ARGS)
ri_PerformCheck(&qkey, qplan,
fk_rel, pk_rel,
old_row, NULL,
true, /* must detect new rows */
SPI_OK_SELECT,
tgargs[RI_CONSTRAINT_NAME_ARGNO]);
@@ -1102,6 +1108,7 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
ri_PerformCheck(&qkey, qplan,
fk_rel, pk_rel,
old_row, NULL,
true, /* must detect new rows */
SPI_OK_DELETE,
tgargs[RI_CONSTRAINT_NAME_ARGNO]);
@@ -1285,6 +1292,7 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
ri_PerformCheck(&qkey, qplan,
fk_rel, pk_rel,
old_row, new_row,
true, /* must detect new rows */
SPI_OK_UPDATE,
tgargs[RI_CONSTRAINT_NAME_ARGNO]);
@@ -1453,6 +1461,7 @@ RI_FKey_restrict_del(PG_FUNCTION_ARGS)
ri_PerformCheck(&qkey, qplan,
fk_rel, pk_rel,
old_row, NULL,
true, /* must detect new rows */
SPI_OK_SELECT,
tgargs[RI_CONSTRAINT_NAME_ARGNO]);
@@ -1633,6 +1642,7 @@ RI_FKey_restrict_upd(PG_FUNCTION_ARGS)
ri_PerformCheck(&qkey, qplan,
fk_rel, pk_rel,
old_row, NULL,
true, /* must detect new rows */
SPI_OK_SELECT,
tgargs[RI_CONSTRAINT_NAME_ARGNO]);
@@ -1802,6 +1812,7 @@ RI_FKey_setnull_del(PG_FUNCTION_ARGS)
ri_PerformCheck(&qkey, qplan,
fk_rel, pk_rel,
old_row, NULL,
true, /* must detect new rows */
SPI_OK_UPDATE,
tgargs[RI_CONSTRAINT_NAME_ARGNO]);
@@ -2019,6 +2030,7 @@ RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
ri_PerformCheck(&qkey, qplan,
fk_rel, pk_rel,
old_row, NULL,
true, /* must detect new rows */
SPI_OK_UPDATE,
tgargs[RI_CONSTRAINT_NAME_ARGNO]);
@@ -2188,6 +2200,7 @@ RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
ri_PerformCheck(&qkey, qplan,
fk_rel, pk_rel,
old_row, NULL,
true, /* must detect new rows */
SPI_OK_UPDATE,
tgargs[RI_CONSTRAINT_NAME_ARGNO]);
@@ -2392,6 +2405,7 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
ri_PerformCheck(&qkey, qplan,
fk_rel, pk_rel,
old_row, NULL,
true, /* must detect new rows */
SPI_OK_UPDATE,
tgargs[RI_CONSTRAINT_NAME_ARGNO]);
@@ -2788,11 +2802,13 @@ static bool
ri_PerformCheck(RI_QueryKey *qkey, void *qplan,
Relation fk_rel, Relation pk_rel,
HeapTuple old_tuple, HeapTuple new_tuple,
bool detectNewRows,
int expect_OK, const char *constrname)
{
Relation query_rel,
source_rel;
int key_idx;
bool useCurrentSnapshot;
int limit;
int spi_result;
AclId save_uid;
@@ -2842,9 +2858,25 @@ ri_PerformCheck(RI_QueryKey *qkey, void *qplan,
vals, nulls);
}
/* Switch to proper UID to perform check as */
save_uid = GetUserId();
SetUserId(RelationGetForm(query_rel)->relowner);
/*
* In READ COMMITTED mode, we just need to make sure the regular query
* snapshot is up-to-date, and we will see all rows that could be
* interesting. In SERIALIZABLE mode, we can't update the regular query
* snapshot. If the caller passes detectNewRows == false then it's okay
* to do the query with the transaction snapshot; otherwise we tell the
* executor to force a current snapshot (and error out if it finds any
* rows under current snapshot that wouldn't be visible per the
* transaction snapshot).
*/
if (XactIsoLevel == XACT_SERIALIZABLE)
{
useCurrentSnapshot = detectNewRows;
}
else
{
SetQuerySnapshot();
useCurrentSnapshot = false;
}
/*
* If this is a select query (e.g., for a 'no action' or 'restrict'
@@ -2854,19 +2886,20 @@ ri_PerformCheck(RI_QueryKey *qkey, void *qplan,
*/
limit = (expect_OK == SPI_OK_SELECT) ? 1 : 0;
/*
* Run the plan, using SnapshotNow time qual rules so that we can see
* all committed tuples, even those committed after our own transaction
* or query started.
*/
spi_result = SPI_execp_now(qplan, vals, nulls, limit);
/* Switch to proper UID to perform check as */
save_uid = GetUserId();
SetUserId(RelationGetForm(query_rel)->relowner);
/* Finally we can run the query. */
spi_result = SPI_execp_current(qplan, vals, nulls,
useCurrentSnapshot, limit);
/* Restore UID */
SetUserId(save_uid);
/* Check result */
if (spi_result < 0)
elog(ERROR, "SPI_execp_now returned %d", spi_result);
elog(ERROR, "SPI_execp_current returned %d", spi_result);
if (expect_OK >= 0 && spi_result != expect_OK)
ri_ReportViolation(qkey, constrname ? constrname : "",

60
src/backend/utils/time/tqual.c
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 1.69 2003/09/25 18:58:35 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/time/tqual.c,v 1.70 2003/10/01 21:30:52 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -26,14 +26,19 @@
#include "storage/sinval.h"
#include "utils/tqual.h"
static SnapshotData SnapshotDirtyData;
Snapshot SnapshotDirty = &SnapshotDirtyData;
/*
* The SnapshotData structs are static to simplify memory allocation
* (see the hack in GetSnapshotData to avoid repeated malloc/free).
*/
static SnapshotData QuerySnapshotData;
static SnapshotData SerializableSnapshotData;
static SnapshotData CurrentSnapshotData;
static SnapshotData SnapshotDirtyData;
/* Externally visible pointers to valid snapshots: */
Snapshot QuerySnapshot = NULL;
Snapshot SerializableSnapshot = NULL;
Snapshot SnapshotDirty = &SnapshotDirtyData;
/* These are updated by GetSnapshotData: */
TransactionId RecentXmin = InvalidTransactionId;
@@ -387,10 +392,8 @@ HeapTupleSatisfiesToast(HeapTupleHeader tuple)
* CurrentCommandId.
*/
int
HeapTupleSatisfiesUpdate(HeapTuple htuple, CommandId curcid)
HeapTupleSatisfiesUpdate(HeapTupleHeader tuple, CommandId curcid)
{
HeapTupleHeader tuple = htuple->t_data;
if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
{
if (tuple->t_infomask & HEAP_XMIN_INVALID)
@@ -1023,6 +1026,42 @@ CopyQuerySnapshot(void)
return snapshot;
}
/*
* CopyCurrentSnapshot
* Make a snapshot that is up-to-date as of the current instant,
* and return a copy.
*
* The copy is palloc'd in the current memory context.
*/
Snapshot
CopyCurrentSnapshot(void)
{
Snapshot currentSnapshot;
Snapshot snapshot;
if (QuerySnapshot == NULL) /* should not be first call in xact */
elog(ERROR, "no snapshot has been set");
/* Update the static struct */
currentSnapshot = GetSnapshotData(&CurrentSnapshotData, false);
currentSnapshot->curcid = GetCurrentCommandId();
/* Make a copy */
snapshot = (Snapshot) palloc(sizeof(SnapshotData));
memcpy(snapshot, currentSnapshot, sizeof(SnapshotData));
if (snapshot->xcnt > 0)
{
snapshot->xip = (TransactionId *)
palloc(snapshot->xcnt * sizeof(TransactionId));
memcpy(snapshot->xip, currentSnapshot->xip,
snapshot->xcnt * sizeof(TransactionId));
}
else
snapshot->xip = NULL;
return snapshot;
}
/*
* FreeXactSnapshot
* Free snapshot(s) at end of transaction.
@@ -1031,8 +1070,9 @@ void
FreeXactSnapshot(void)
{
/*
* We do not free(QuerySnapshot->xip); or
* free(SerializableSnapshot->xip); they will be reused soon
* We do not free the xip arrays for the snapshot structs;
* they will be reused soon. So this is now just a state
* change to prevent outside callers from accessing the snapshots.
*/
QuerySnapshot = NULL;
SerializableSnapshot = NULL;