diff options
Diffstat (limited to 'src/backend/storage/freespace/freespace.c')
| -rw-r--r-- | src/backend/storage/freespace/freespace.c | 42 |
1 files changed, 13 insertions, 29 deletions
diff --git a/src/backend/storage/freespace/freespace.c b/src/backend/storage/freespace/freespace.c index 2383094cfd1..7e8e7e79a3d 100644 --- a/src/backend/storage/freespace/freespace.c +++ b/src/backend/storage/freespace/freespace.c @@ -247,16 +247,18 @@ GetRecordedFreeSpace(Relation rel, BlockNumber heapBlk) } /* - * FreeSpaceMapTruncateRel - adjust for truncation of a relation. - * - * The caller must hold AccessExclusiveLock on the relation, to ensure that - * other backends receive the smgr invalidation event that this function sends - * before they access the FSM again. + * FreeSpaceMapPrepareTruncateRel - prepare for truncation of a relation. * * nblocks is the new size of the heap. + * + * Return the number of blocks of new FSM. + * If it's InvalidBlockNumber, there is nothing to truncate; + * otherwise the caller is responsible for calling smgrtruncate() + * to truncate the FSM pages, and FreeSpaceMapVacuumRange() + * to update upper-level pages in the FSM. */ -void -FreeSpaceMapTruncateRel(Relation rel, BlockNumber nblocks) +BlockNumber +FreeSpaceMapPrepareTruncateRel(Relation rel, BlockNumber nblocks) { BlockNumber new_nfsmblocks; FSMAddress first_removed_address; @@ -270,7 +272,7 @@ FreeSpaceMapTruncateRel(Relation rel, BlockNumber nblocks) * truncate. */ if (!smgrexists(rel->rd_smgr, FSM_FORKNUM)) - return; + return InvalidBlockNumber; /* Get the location in the FSM of the first removed heap block */ first_removed_address = fsm_get_location(nblocks, &first_removed_slot); @@ -285,7 +287,7 @@ FreeSpaceMapTruncateRel(Relation rel, BlockNumber nblocks) { buf = fsm_readbuf(rel, first_removed_address, false); if (!BufferIsValid(buf)) - return; /* nothing to do; the FSM was already smaller */ + return InvalidBlockNumber; /* nothing to do; the FSM was already smaller */ LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE); /* NO EREPORT(ERROR) from here till changes are logged */ @@ -315,28 +317,10 @@ FreeSpaceMapTruncateRel(Relation rel, BlockNumber nblocks) { new_nfsmblocks = fsm_logical_to_physical(first_removed_address); if (smgrnblocks(rel->rd_smgr, FSM_FORKNUM) <= new_nfsmblocks) - return; /* nothing to do; the FSM was already smaller */ + return InvalidBlockNumber; /* nothing to do; the FSM was already smaller */ } - /* Truncate the unused FSM pages, and send smgr inval message */ - smgrtruncate(rel->rd_smgr, FSM_FORKNUM, new_nfsmblocks); - - /* - * We might as well update the local smgr_fsm_nblocks setting. - * smgrtruncate sent an smgr cache inval message, which will cause other - * backends to invalidate their copy of smgr_fsm_nblocks, and this one too - * at the next command boundary. But this ensures it isn't outright wrong - * until then. - */ - if (rel->rd_smgr) - rel->rd_smgr->smgr_fsm_nblocks = new_nfsmblocks; - - /* - * Update upper-level FSM pages to account for the truncation. This is - * important because the just-truncated pages were likely marked as - * all-free, and would be preferentially selected. - */ - FreeSpaceMapVacuumRange(rel, nblocks, InvalidBlockNumber); + return new_nfsmblocks; } /* |