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| author | Heikki Linnakangas <heikki.linnakangas@iki.fi> | 2015-06-26 12:38:24 +0300 |
|---|---|---|
| committer | Heikki Linnakangas <heikki.linnakangas@iki.fi> | 2015-06-26 12:38:24 +0300 |
| commit | 4b8e24b9ad308c30dbe2184e06848e638e018114 (patch) | |
| tree | 75aa34a22d85cf402477a97991a1513de657dcc8 | |
| parent | f7bb7f0625771bc71869cdadafcf54450b2db08f (diff) | |
| download | postgresql-4b8e24b9ad308c30dbe2184e06848e638e018114.tar.gz postgresql-4b8e24b9ad308c30dbe2184e06848e638e018114.zip | |
Fix a couple of bugs with wal_log_hints.
1. Replay of the WAL record for setting a bit in the visibility map
contained an assertion that a full-page image of that record type can only
occur with checksums enabled. But it can also happen with wal_log_hints, so
remove the assertion. Unlike checksums, wal_log_hints can be changed on the
fly, so it would be complicated to figure out if it was enabled at the time
that the WAL record was generated.
2. wal_log_hints has the same effect on the locking needed to read the LSN
of a page as data checksums. BufferGetLSNAtomic() didn't get the memo.
Backpatch to 9.4, where wal_log_hints was added.
| -rw-r--r-- | src/backend/access/heap/heapam.c | 15 | ||||
| -rw-r--r-- | src/backend/storage/buffer/bufmgr.c | 2 |
2 files changed, 9 insertions, 8 deletions
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index caacc105d25..208457584d9 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -7479,10 +7479,11 @@ heap_xlog_visible(XLogReaderState *record) { /* * We don't bump the LSN of the heap page when setting the visibility - * map bit (unless checksums are enabled, in which case we must), - * because that would generate an unworkable volume of full-page - * writes. This exposes us to torn page hazards, but since we're not - * inspecting the existing page contents in any way, we don't care. + * map bit (unless checksums or wal_hint_bits is enabled, in which + * case we must), because that would generate an unworkable volume of + * full-page writes. This exposes us to torn page hazards, but since + * we're not inspecting the existing page contents in any way, we + * don't care. * * However, all operations that clear the visibility map bit *do* bump * the LSN, and those operations will only be replayed if the XLOG LSN @@ -7497,10 +7498,10 @@ heap_xlog_visible(XLogReaderState *record) else if (action == BLK_RESTORED) { /* - * If heap block was backed up, restore it. This can only happen with - * checksums enabled. + * If heap block was backed up, we already restored it and there's + * nothing more to do. (This can only happen with checksums or + * wal_log_hints enabled.) */ - Assert(DataChecksumsEnabled()); } if (BufferIsValid(buffer)) UnlockReleaseBuffer(buffer); diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c index cc973b53a91..e4b25587e98 100644 --- a/src/backend/storage/buffer/bufmgr.c +++ b/src/backend/storage/buffer/bufmgr.c @@ -2496,7 +2496,7 @@ BufferGetLSNAtomic(Buffer buffer) /* * If we don't need locking for correctness, fastpath out. */ - if (!DataChecksumsEnabled() || BufferIsLocal(buffer)) + if (!XLogHintBitIsNeeded() || BufferIsLocal(buffer)) return PageGetLSN(page); /* Make sure we've got a real buffer, and that we hold a pin on it. */ |