database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-11-07 19:06:32 +03:00
Code Activity

Cache smgrnblocks() results in recovery.

Browse Source 
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
This commit is contained in:
Thomas Munro
2020-07-31 14:15:18 +12:00
parent e3931d01f3
commit c5315f4f44
6 changed files with 66 additions and 46 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
src/backend/storage/freespace/freespace.c
View File

@@ -541,18 +541,19 @@ fsm_readbuf(Relation rel, FSMAddress addr, bool extend)
* value might be stale. (We send smgr inval messages on truncation, but
* not on extension.)
*/
if (rel->rd_smgr->smgr_fsm_nblocks == InvalidBlockNumber ||
blkno >= rel->rd_smgr->smgr_fsm_nblocks)
if (rel->rd_smgr->smgr_cached_nblocks[FSM_FORKNUM] == InvalidBlockNumber ||
blkno >= rel->rd_smgr->smgr_cached_nblocks[FSM_FORKNUM])
{
/* Invalidate the cache so smgrnblocks asks the kernel. */
rel->rd_smgr->smgr_cached_nblocks[FSM_FORKNUM] = InvalidBlockNumber;
if (smgrexists(rel->rd_smgr, FSM_FORKNUM))
rel->rd_smgr->smgr_fsm_nblocks = smgrnblocks(rel->rd_smgr,
FSM_FORKNUM);
smgrnblocks(rel->rd_smgr, FSM_FORKNUM);
else
rel->rd_smgr->smgr_fsm_nblocks = 0;
rel->rd_smgr->smgr_cached_nblocks[FSM_FORKNUM] = 0;
}
/* Handle requests beyond EOF */
if (blkno >= rel->rd_smgr->smgr_fsm_nblocks)
if (blkno >= rel->rd_smgr->smgr_cached_nblocks[FSM_FORKNUM])
{
if (extend)
fsm_extend(rel, blkno + 1);
@@ -621,14 +622,17 @@ fsm_extend(Relation rel, BlockNumber fsm_nblocks)
RelationOpenSmgr(rel);
/*
* Create the FSM file first if it doesn't exist. If smgr_fsm_nblocks is
* positive then it must exist, no need for an smgrexists call.
* Create the FSM file first if it doesn't exist. If
* smgr_cached_nblocks[FSM_FORKNUM] is positive then it must exist, no
* need for an smgrexists call.
*/
if ((rel->rd_smgr->smgr_fsm_nblocks == 0 ||
rel->rd_smgr->smgr_fsm_nblocks == InvalidBlockNumber) &&
if ((rel->rd_smgr->smgr_cached_nblocks[FSM_FORKNUM] == 0 ||
rel->rd_smgr->smgr_cached_nblocks[FSM_FORKNUM] == InvalidBlockNumber) &&
!smgrexists(rel->rd_smgr, FSM_FORKNUM))
smgrcreate(rel->rd_smgr, FSM_FORKNUM, false);
/* Invalidate cache so that smgrnblocks() asks the kernel. */
rel->rd_smgr->smgr_cached_nblocks[FSM_FORKNUM] = InvalidBlockNumber;
fsm_nblocks_now = smgrnblocks(rel->rd_smgr, FSM_FORKNUM);
while (fsm_nblocks_now < fsm_nblocks)
@@ -640,9 +644,6 @@ fsm_extend(Relation rel, BlockNumber fsm_nblocks)
fsm_nblocks_now++;
}
/* Update local cache with the up-to-date size */
rel->rd_smgr->smgr_fsm_nblocks = fsm_nblocks_now;
UnlockRelationForExtension(rel, ExclusiveLock);
}