diff options
Diffstat (limited to 'src/backend/tcop/pquery.c')
| -rw-r--r-- | src/backend/tcop/pquery.c | 27 |
1 files changed, 20 insertions, 7 deletions
diff --git a/src/backend/tcop/pquery.c b/src/backend/tcop/pquery.c index b5797042abc..960f3fadce5 100644 --- a/src/backend/tcop/pquery.c +++ b/src/backend/tcop/pquery.c @@ -480,7 +480,9 @@ PortalStart(Portal portal, ParamListInfo params, * We could remember the snapshot in portal->portalSnapshot, * but presently there seems no need to, as this code path * cannot be used for non-atomic execution. Hence there can't - * be any commit/abort that might destroy the snapshot. + * be any commit/abort that might destroy the snapshot. Since + * we don't do that, there's also no need to force a + * non-default nesting level for the snapshot. */ /* @@ -1136,9 +1138,15 @@ PortalRunUtility(Portal portal, PlannedStmt *pstmt, snapshot = RegisterSnapshot(snapshot); portal->holdSnapshot = snapshot; } - /* In any case, make the snapshot active and remember it in portal */ - PushActiveSnapshot(snapshot); - /* PushActiveSnapshot might have copied the snapshot */ + + /* + * In any case, make the snapshot active and remember it in portal. + * Because the portal now references the snapshot, we must tell + * snapmgr.c that the snapshot belongs to the portal's transaction + * level, else we risk portalSnapshot becoming a dangling pointer. + */ + PushActiveSnapshotWithLevel(snapshot, portal->createLevel); + /* PushActiveSnapshotWithLevel might have copied the snapshot */ portal->portalSnapshot = GetActiveSnapshot(); } else @@ -1784,8 +1792,13 @@ EnsurePortalSnapshotExists(void) elog(ERROR, "cannot execute SQL without an outer snapshot or portal"); Assert(portal->portalSnapshot == NULL); - /* Create a new snapshot and make it active */ - PushActiveSnapshot(GetTransactionSnapshot()); - /* PushActiveSnapshot might have copied the snapshot */ + /* + * Create a new snapshot, make it active, and remember it in portal. + * Because the portal now references the snapshot, we must tell snapmgr.c + * that the snapshot belongs to the portal's transaction level, else we + * risk portalSnapshot becoming a dangling pointer. + */ + PushActiveSnapshotWithLevel(GetTransactionSnapshot(), portal->createLevel); + /* PushActiveSnapshotWithLevel might have copied the snapshot */ portal->portalSnapshot = GetActiveSnapshot(); } |