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| author | Thomas Munro <tmunro@postgresql.org> | 2020-07-31 14:15:18 +1200 |
|---|---|---|
| committer | Thomas Munro <tmunro@postgresql.org> | 2020-07-31 14:29:52 +1200 |
| commit | c5315f4f44843c20ada876fdb0d0828795dfbdf5 (patch) | |
| tree | b94c24609a31ae7243b217ae7d5358c8cff8fe20 /src/backend/access/heap/visibilitymap.c | |
| parent | e3931d01f3afef14703827eda1dad0a3fb3b5d07 (diff) | |
| download | postgresql-c5315f4f44843c20ada876fdb0d0828795dfbdf5.tar.gz postgresql-c5315f4f44843c20ada876fdb0d0828795dfbdf5.zip | |
Cache smgrnblocks() results in recovery.
Avoid repeatedly calling lseek(SEEK_END) during recovery by caching
the size of each fork. For now, we can't use the same technique in
other processes, because we lack a shared invalidation mechanism.
Do this by generalizing the pre-existing caching used by FSM and VM
to support all forks.
Discussion: https://postgr.es/m/CAEepm%3D3SSw-Ty1DFcK%3D1rU-K6GSzYzfdD4d%2BZwapdN7dTa6%3DnQ%40mail.gmail.com
Diffstat (limited to 'src/backend/access/heap/visibilitymap.c')
| -rw-r--r-- | src/backend/access/heap/visibilitymap.c | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/src/backend/access/heap/visibilitymap.c b/src/backend/access/heap/visibilitymap.c index 0a51678c40d..b1072183bcd 100644 --- a/src/backend/access/heap/visibilitymap.c +++ b/src/backend/access/heap/visibilitymap.c @@ -561,17 +561,16 @@ vm_readbuf(Relation rel, BlockNumber blkno, bool extend) * If we haven't cached the size of the visibility map fork yet, check it * first. */ - if (rel->rd_smgr->smgr_vm_nblocks == InvalidBlockNumber) + if (rel->rd_smgr->smgr_cached_nblocks[VISIBILITYMAP_FORKNUM] == InvalidBlockNumber) { if (smgrexists(rel->rd_smgr, VISIBILITYMAP_FORKNUM)) - rel->rd_smgr->smgr_vm_nblocks = smgrnblocks(rel->rd_smgr, - VISIBILITYMAP_FORKNUM); + smgrnblocks(rel->rd_smgr, VISIBILITYMAP_FORKNUM); else - rel->rd_smgr->smgr_vm_nblocks = 0; + rel->rd_smgr->smgr_cached_nblocks[VISIBILITYMAP_FORKNUM] = 0; } /* Handle requests beyond EOF */ - if (blkno >= rel->rd_smgr->smgr_vm_nblocks) + if (blkno >= rel->rd_smgr->smgr_cached_nblocks[VISIBILITYMAP_FORKNUM]) { if (extend) vm_extend(rel, blkno + 1); @@ -641,11 +640,13 @@ vm_extend(Relation rel, BlockNumber vm_nblocks) * Create the file first if it doesn't exist. If smgr_vm_nblocks is * positive then it must exist, no need for an smgrexists call. */ - if ((rel->rd_smgr->smgr_vm_nblocks == 0 || - rel->rd_smgr->smgr_vm_nblocks == InvalidBlockNumber) && + if ((rel->rd_smgr->smgr_cached_nblocks[VISIBILITYMAP_FORKNUM] == 0 || + rel->rd_smgr->smgr_cached_nblocks[VISIBILITYMAP_FORKNUM] == InvalidBlockNumber) && !smgrexists(rel->rd_smgr, VISIBILITYMAP_FORKNUM)) smgrcreate(rel->rd_smgr, VISIBILITYMAP_FORKNUM, false); + /* Invalidate cache so that smgrnblocks() asks the kernel. */ + rel->rd_smgr->smgr_cached_nblocks[VISIBILITYMAP_FORKNUM] = InvalidBlockNumber; vm_nblocks_now = smgrnblocks(rel->rd_smgr, VISIBILITYMAP_FORKNUM); /* Now extend the file */ @@ -667,8 +668,5 @@ vm_extend(Relation rel, BlockNumber vm_nblocks) */ CacheInvalidateSmgr(rel->rd_smgr->smgr_rnode); - /* Update local cache with the up-to-date size */ - rel->rd_smgr->smgr_vm_nblocks = vm_nblocks_now; - UnlockRelationForExtension(rel, ExclusiveLock); } |