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| author | Thomas Munro <tmunro@postgresql.org> | 2020-01-31 10:25:34 +1300 |
|---|---|---|
| committer | Thomas Munro <tmunro@postgresql.org> | 2020-01-31 11:12:21 +1300 |
| commit | 2c56b3ac436db2d24aa11bdd22f45becf2030607 (patch) | |
| tree | 8ff6f920b41483110cc07e15dd52a7d864a3e055 | |
| parent | a5b652f3a0110f81d2433855ab6bec136f92db83 (diff) | |
| download | postgresql-2c56b3ac436db2d24aa11bdd22f45becf2030607.tar.gz postgresql-2c56b3ac436db2d24aa11bdd22f45becf2030607.zip | |
Handle lack of DSM slots in parallel btree build.
If no DSM slots are available, a ParallelContext can still be
created, but its seg pointer is NULL. Teach parallel btree build
to cope with that by falling back to a regular non-parallel build,
to avoid crashing with a segmentation fault.
Back-patch to 11, where parallel CREATE INDEX landed.
Reported-by: Nicola Contu
Reviewed-by: Peter Geoghegan
Discussion: https://postgr.es/m/CA%2BhUKGJgJEBnkuODBVomyK3MWFvDBbMVj%3Dgdt6DnRPU-5sQ6UQ%40mail.gmail.com
| -rw-r--r-- | src/backend/access/nbtree/nbtsort.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/src/backend/access/nbtree/nbtsort.c b/src/backend/access/nbtree/nbtsort.c index 16f57557776..bc00799b964 100644 --- a/src/backend/access/nbtree/nbtsort.c +++ b/src/backend/access/nbtree/nbtsort.c @@ -1256,6 +1256,15 @@ _bt_begin_parallel(BTBuildState *buildstate, bool isconcurrent, int request) Assert(request > 0); pcxt = CreateParallelContext("postgres", "_bt_parallel_build_main", request, true); + + /* If no DSM segment was available, back out (do serial build) */ + if (pcxt->seg == NULL) + { + DestroyParallelContext(pcxt); + ExitParallelMode(); + return; + } + scantuplesortstates = leaderparticipates ? request + 1 : request; /* |