diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/executor/execMain.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c index 13f3fcdaee9..1c12d6ebff0 100644 --- a/src/backend/executor/execMain.c +++ b/src/backend/executor/execMain.c @@ -348,7 +348,16 @@ standard_ExecutorRun(QueryDesc *queryDesc, dest->rStartup(dest, operation, queryDesc->tupDesc); /* - * run plan + * Run plan, unless direction is NoMovement. + * + * Note: pquery.c selects NoMovement if a prior call already reached + * end-of-data in the user-specified fetch direction. This is important + * because various parts of the executor can misbehave if called again + * after reporting EOF. For example, heapam.c would actually restart a + * heapscan and return all its data afresh. There is also some doubt + * about whether a parallel plan would operate properly if an additional, + * necessarily non-parallel execution request occurs after completing a + * parallel execution. (That case should work, but it's untested.) */ if (!ScanDirectionIsNoMovement(direction)) ExecutePlan(queryDesc, |