diff options
Diffstat (limited to 'src/backend/storage/freespace/freespace.c')
| -rw-r--r-- | src/backend/storage/freespace/freespace.c | 62 |
1 files changed, 33 insertions, 29 deletions
diff --git a/src/backend/storage/freespace/freespace.c b/src/backend/storage/freespace/freespace.c index db98f7254d9..9def3df7483 100644 --- a/src/backend/storage/freespace/freespace.c +++ b/src/backend/storage/freespace/freespace.c @@ -8,7 +8,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/storage/freespace/freespace.c,v 1.33 2004/08/29 04:12:47 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/storage/freespace/freespace.c,v 1.34 2004/08/29 05:06:47 momjian Exp $ * * * NOTES: @@ -217,7 +217,8 @@ int MaxFSMRelations; /* these are set by guc.c */ int MaxFSMPages; static FSMHeader *FreeSpaceMap; /* points to FSMHeader in shared memory */ -static HTAB *FreeSpaceMapRelHash; /* points to (what used to be) FSMHeader->relHash */ +static HTAB *FreeSpaceMapRelHash; /* points to (what used to be) + * FSMHeader->relHash */ static FSMRelation *lookup_fsm_rel(RelFileNode *rel); @@ -265,10 +266,10 @@ InitFreeSpaceMap(void) { HASHCTL info; int nchunks; - bool found; + bool found; /* Create table header */ - FreeSpaceMap = (FSMHeader *) ShmemInitStruct("Free Space Map Header",sizeof(FSMHeader),&found); + FreeSpaceMap = (FSMHeader *) ShmemInitStruct("Free Space Map Header", sizeof(FSMHeader), &found); if (FreeSpaceMap == NULL) ereport(FATAL, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -282,10 +283,10 @@ InitFreeSpaceMap(void) info.hash = tag_hash; FreeSpaceMapRelHash = ShmemInitHash("Free Space Map Hash", - MaxFSMRelations / 10, - MaxFSMRelations, - &info, - (HASH_ELEM | HASH_FUNCTION)); + MaxFSMRelations / 10, + MaxFSMRelations, + &info, + (HASH_ELEM | HASH_FUNCTION)); if (!FreeSpaceMapRelHash) ereport(FATAL, @@ -1440,24 +1441,25 @@ compact_fsm_storage(void) /* * It's possible that we have to move data down, not up, if the - * allocations of previous rels expanded. This normally means that - * our allocation expanded too (or at least got no worse), and - * ditto for later rels. So there should be room to move all our - * data down without dropping any --- but we might have to push down - * following rels to acquire the room. We don't want to do the push - * more than once, so pack everything against the end of the arena - * if so. + * allocations of previous rels expanded. This normally means + * that our allocation expanded too (or at least got no worse), + * and ditto for later rels. So there should be room to move all + * our data down without dropping any --- but we might have to + * push down following rels to acquire the room. We don't want to + * do the push more than once, so pack everything against the end + * of the arena if so. * * In corner cases where we are on the short end of a roundoff choice * that we were formerly on the long end of, it's possible that we - * have to move down and compress our data too. In fact, even after - * pushing down the following rels, there might not be as much space - * as we computed for this rel above --- that would imply that some - * following rel(s) are also on the losing end of roundoff choices. - * We could handle this fairly by doing the per-rel compactions - * out-of-order, but that seems like way too much complexity to deal - * with a very infrequent corner case. Instead, we simply drop pages - * from the end of the current rel's data until it fits. + * have to move down and compress our data too. In fact, even + * after pushing down the following rels, there might not be as + * much space as we computed for this rel above --- that would + * imply that some following rel(s) are also on the losing end of + * roundoff choices. We could handle this fairly by doing the + * per-rel compactions out-of-order, but that seems like way too + * much complexity to deal with a very infrequent corner case. + * Instead, we simply drop pages from the end of the current rel's + * data until it fits. */ if (newChunkIndex > oldChunkIndex) { @@ -1491,12 +1493,14 @@ compact_fsm_storage(void) { /* uh-oh, forcibly cut the allocation to fit */ newAlloc = limitChunkIndex - newChunkIndex; + /* - * If newAlloc < 0 at this point, we are moving the rel's - * firstChunk into territory currently assigned to a later - * rel. This is okay so long as we do not copy any data. - * The rels will be back in nondecreasing firstChunk order - * at completion of the compaction pass. + * If newAlloc < 0 at this point, we are moving the + * rel's firstChunk into territory currently assigned + * to a later rel. This is okay so long as we do not + * copy any data. The rels will be back in + * nondecreasing firstChunk order at completion of the + * compaction pass. */ if (newAlloc < 0) newAlloc = 0; @@ -1846,7 +1850,7 @@ DumpFreeSpace(void) relNum++; fprintf(stderr, "Map %d: rel %u/%u/%u isIndex %d avgRequest %u lastPageCount %d nextPage %d\nMap= ", relNum, - fsmrel->key.spcNode, fsmrel->key.dbNode, fsmrel->key.relNode, + fsmrel->key.spcNode, fsmrel->key.dbNode, fsmrel->key.relNode, (int) fsmrel->isIndex, fsmrel->avgRequest, fsmrel->lastPageCount, fsmrel->nextPage); if (fsmrel->isIndex) |