diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/commands/portalcmds.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/src/backend/commands/portalcmds.c b/src/backend/commands/portalcmds.c index 3ea30bcbc99..b8590d422b6 100644 --- a/src/backend/commands/portalcmds.c +++ b/src/backend/commands/portalcmds.c @@ -358,6 +358,8 @@ PersistHoldablePortal(Portal portal) savePortalContext = PortalContext; PG_TRY(); { + ScanDirection direction = ForwardScanDirection; + ActivePortal = portal; if (portal->resowner) CurrentResourceOwner = portal->resowner; @@ -380,10 +382,20 @@ PersistHoldablePortal(Portal portal) } else { - /* We must reset the cursor state as though at start of query */ + /* Disallow moving backwards from here */ portal->atStart = true; - portal->atEnd = false; portal->portalPos = 0; + + /* + * If we already reached end-of-query, set the direction to + * NoMovement to avoid trying to fetch any tuples. (This check + * exists because not all plan node types are robust about being + * called again if they've already returned NULL once.) We'll + * still set up an empty tuplestore, though, to keep this from + * being a special case later. + */ + if (portal->atEnd) + direction = NoMovementScanDirection; } /* @@ -400,7 +412,7 @@ PersistHoldablePortal(Portal portal) NULL); /* Fetch the result set into the tuplestore */ - ExecutorRun(queryDesc, ForwardScanDirection, 0L, false); + ExecutorRun(queryDesc, direction, 0L, false); queryDesc->dest->rDestroy(queryDesc->dest); queryDesc->dest = NULL; |