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| author | Robert Haas <rhaas@postgresql.org> | 2017-11-28 12:05:52 -0500 |
|---|---|---|
| committer | Robert Haas <rhaas@postgresql.org> | 2017-11-28 12:19:19 -0500 |
| commit | dba6e75c1113dbfc7b10d93cc6c0babd8b7d852b (patch) | |
| tree | a7ffa4b9cbe774b91f85e953c3a608e5220cb67b /src | |
| parent | ec7629dfb98a34cf4e459cf6b27febfd33ae9ad5 (diff) | |
| download | postgresql-dba6e75c1113dbfc7b10d93cc6c0babd8b7d852b.tar.gz postgresql-dba6e75c1113dbfc7b10d93cc6c0babd8b7d852b.zip | |
Fix ReinitializeParallelDSM to tolerate finding no error queues.
Commit d4663350646ca0c069a36d906155a0f7e3372eb7 changed things so
that shm_toc_lookup would fail with an error rather than silently
returning NULL in the hope that such failures would be reported
in a useful way rather than via a system crash. However, it
overlooked the fact that the lookup of PARALLEL_KEY_ERROR_QUEUE
in ReinitializeParallelDSM is expected to fail when no DSM segment
was created in the first place; in that case, we end up with a
backend-private memory segment that still contains an entry for
PARALLEL_KEY_FIXED but no others. Consequently a benign failure
to initialize parallelism can escalate into an elog(ERROR);
repair.
Discussion: http://postgr.es/m/CA+Tgmob8LFw55DzH1QEREpBEA9RJ_W_amhBFCVZ6WMwUhVpOqg@mail.gmail.com
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/access/transam/parallel.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c index e1a6a75a872..afef608d70f 100644 --- a/src/backend/access/transam/parallel.c +++ b/src/backend/access/transam/parallel.c @@ -399,9 +399,10 @@ ReinitializeParallelDSM(ParallelContext *pcxt) fps = shm_toc_lookup(pcxt->toc, PARALLEL_KEY_FIXED, false); fps->last_xlog_end = 0; - /* Recreate error queues. */ + /* Recreate error queues (if they exist). */ error_queue_space = - shm_toc_lookup(pcxt->toc, PARALLEL_KEY_ERROR_QUEUE, false); + shm_toc_lookup(pcxt->toc, PARALLEL_KEY_ERROR_QUEUE, true); + Assert(pcxt->nworkers == 0 || error_queue_space != NULL); for (i = 0; i < pcxt->nworkers; ++i) { char *start; |