diff options
Diffstat (limited to 'contrib/pg_visibility/pg_visibility.c')
| -rw-r--r-- | contrib/pg_visibility/pg_visibility.c | 29 |
1 files changed, 23 insertions, 6 deletions
diff --git a/contrib/pg_visibility/pg_visibility.c b/contrib/pg_visibility/pg_visibility.c index 5d0deaba61e..f97373e52e9 100644 --- a/contrib/pg_visibility/pg_visibility.c +++ b/contrib/pg_visibility/pg_visibility.c @@ -19,6 +19,7 @@ #include "funcapi.h" #include "miscadmin.h" #include "storage/bufmgr.h" +#include "storage/proc.h" #include "storage/procarray.h" #include "storage/read_stream.h" #include "storage/smgr.h" @@ -390,6 +391,7 @@ pg_truncate_visibility_map(PG_FUNCTION_ARGS) Relation rel; ForkNumber fork; BlockNumber block; + BlockNumber old_block; rel = relation_open(relid, AccessExclusiveLock); @@ -399,15 +401,22 @@ pg_truncate_visibility_map(PG_FUNCTION_ARGS) /* Forcibly reset cached file size */ RelationGetSmgr(rel)->smgr_cached_nblocks[VISIBILITYMAP_FORKNUM] = InvalidBlockNumber; + /* Compute new and old size before entering critical section. */ + fork = VISIBILITYMAP_FORKNUM; block = visibilitymap_prepare_truncate(rel, 0); - if (BlockNumberIsValid(block)) - { - fork = VISIBILITYMAP_FORKNUM; - smgrtruncate(RelationGetSmgr(rel), &fork, 1, &block); - } + old_block = BlockNumberIsValid(block) ? smgrnblocks(RelationGetSmgr(rel), fork) : 0; + + /* + * WAL-logging, buffer dropping, file truncation must be atomic and all on + * one side of a checkpoint. See RelationTruncate() for discussion. + */ + Assert((MyProc->delayChkptFlags & (DELAY_CHKPT_START | DELAY_CHKPT_COMPLETE)) == 0); + MyProc->delayChkptFlags |= DELAY_CHKPT_START | DELAY_CHKPT_COMPLETE; + START_CRIT_SECTION(); if (RelationNeedsWAL(rel)) { + XLogRecPtr lsn; xl_smgr_truncate xlrec; xlrec.blkno = 0; @@ -417,9 +426,17 @@ pg_truncate_visibility_map(PG_FUNCTION_ARGS) XLogBeginInsert(); XLogRegisterData((char *) &xlrec, sizeof(xlrec)); - XLogInsert(RM_SMGR_ID, XLOG_SMGR_TRUNCATE | XLR_SPECIAL_REL_UPDATE); + lsn = XLogInsert(RM_SMGR_ID, + XLOG_SMGR_TRUNCATE | XLR_SPECIAL_REL_UPDATE); + XLogFlush(lsn); } + if (BlockNumberIsValid(block)) + smgrtruncate(RelationGetSmgr(rel), &fork, 1, &old_block, &block); + + END_CRIT_SECTION(); + MyProc->delayChkptFlags &= ~(DELAY_CHKPT_START | DELAY_CHKPT_COMPLETE); + /* * Release the lock right away, not at commit time. * |