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| author | Robert Haas <rhaas@postgresql.org> | 2011-09-27 08:24:18 -0400 |
|---|---|---|
| committer | Robert Haas <rhaas@postgresql.org> | 2011-09-27 08:24:18 -0400 |
| commit | 624f155ffa93d1af4fb9d91fd5c0eb05da1e9e54 (patch) | |
| tree | 0cf6d5fe8e63fb54f1d972a343b9cb3b52f7004e /src | |
| parent | 269c5dd2f46e3490da05d5dd5dad07828df281d9 (diff) | |
| download | postgresql-624f155ffa93d1af4fb9d91fd5c0eb05da1e9e54.tar.gz postgresql-624f155ffa93d1af4fb9d91fd5c0eb05da1e9e54.zip | |
heap_update() must recheck tuple after unlocking and relocking buffer.
Bug found by Alvaro Herrera, fix suggested by Heikki Linnakangas
and reviewed by Tom Lane.
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/access/heap/heapam.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index 17950d482c1..b2d19016e76 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -2645,13 +2645,16 @@ l2: * visible while we were busy locking the buffer, or during some subsequent * window during which we had it unlocked, we'll have to unlock and * re-lock, to avoid holding the buffer lock across an I/O. That's a bit - * unfortunate, but hopefully shouldn't happen often. + * unfortunate, esepecially since we'll now have to recheck whether the + * tuple has been locked or updated under us, but hopefully it won't + * happen very often. */ if (vmbuffer == InvalidBuffer && PageIsAllVisible(page)) { LockBuffer(buffer, BUFFER_LOCK_UNLOCK); visibilitymap_pin(relation, block, &vmbuffer); LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE); + goto l2; } /* |