diff options
Diffstat (limited to 'src/backend/access/nbtree/nbtree.c')
| -rw-r--r-- | src/backend/access/nbtree/nbtree.c | 152 |
1 files changed, 75 insertions, 77 deletions
diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c index fa5b162c908..c9a7a8b5b29 100644 --- a/src/backend/access/nbtree/nbtree.c +++ b/src/backend/access/nbtree/nbtree.c @@ -12,7 +12,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.151 2006/09/21 20:31:22 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.152 2006/10/04 00:29:49 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -55,7 +55,7 @@ typedef struct BlockNumber *freePages; int nFreePages; /* number of entries in freePages[] */ int maxFreePages; /* allocated size of freePages[] */ - BlockNumber totFreePages; /* true total # of free pages */ + BlockNumber totFreePages; /* true total # of free pages */ MemoryContext pagedelcontext; } BTVacState; @@ -70,7 +70,7 @@ static void btvacuumscan(IndexVacuumInfo *info, IndexBulkDeleteResult *stats, IndexBulkDeleteCallback callback, void *callback_state, BTCycleId cycleid); static void btvacuumpage(BTVacState *vstate, BlockNumber blkno, - BlockNumber orig_blkno); + BlockNumber orig_blkno); /* @@ -109,8 +109,8 @@ btbuild(PG_FUNCTION_ARGS) buildstate.spool = _bt_spoolinit(index, indexInfo->ii_Unique, false); /* - * If building a unique index, put dead tuples in a second spool to - * keep them out of the uniqueness check. + * If building a unique index, put dead tuples in a second spool to keep + * them out of the uniqueness check. */ if (indexInfo->ii_Unique) buildstate.spool2 = _bt_spoolinit(index, false, true); @@ -146,11 +146,11 @@ btbuild(PG_FUNCTION_ARGS) #endif /* BTREE_BUILD_STATS */ /* - * If we are reindexing a pre-existing index, it is critical to send out - * a relcache invalidation SI message to ensure all backends re-read the - * index metapage. We expect that the caller will ensure that happens - * (typically as a side effect of updating index stats, but it must - * happen even if the stats don't change!) + * If we are reindexing a pre-existing index, it is critical to send out a + * relcache invalidation SI message to ensure all backends re-read the + * index metapage. We expect that the caller will ensure that happens + * (typically as a side effect of updating index stats, but it must happen + * even if the stats don't change!) */ /* @@ -252,11 +252,11 @@ btgettuple(PG_FUNCTION_ARGS) if (scan->kill_prior_tuple) { /* - * Yes, remember it for later. (We'll deal with all such tuples + * Yes, remember it for later. (We'll deal with all such tuples * at once right before leaving the index page.) The test for * numKilled overrun is not just paranoia: if the caller reverses * direction in the indexscan then the same item might get entered - * multiple times. It's not worth trying to optimize that, so we + * multiple times. It's not worth trying to optimize that, so we * don't detect it, but instead just forget any excess entries. */ if (so->killedItems == NULL) @@ -316,8 +316,8 @@ btgetmulti(PG_FUNCTION_ARGS) while (ntids < max_tids) { /* - * Advance to next tuple within page. This is the same as the - * easy case in _bt_next(). + * Advance to next tuple within page. This is the same as the easy + * case in _bt_next(). */ if (++so->currPos.itemIndex > so->currPos.lastItem) { @@ -373,7 +373,7 @@ btrescan(PG_FUNCTION_ARGS) so->keyData = (ScanKey) palloc(scan->numberOfKeys * sizeof(ScanKeyData)); else so->keyData = NULL; - so->killedItems = NULL; /* until needed */ + so->killedItems = NULL; /* until needed */ so->numKilled = 0; scan->opaque = so; } @@ -461,9 +461,9 @@ btmarkpos(PG_FUNCTION_ARGS) /* * Just record the current itemIndex. If we later step to next page - * before releasing the marked position, _bt_steppage makes a full copy - * of the currPos struct in markPos. If (as often happens) the mark is - * moved before we leave the page, we don't have to do that work. + * before releasing the marked position, _bt_steppage makes a full copy of + * the currPos struct in markPos. If (as often happens) the mark is moved + * before we leave the page, we don't have to do that work. */ if (BTScanPosIsValid(so->currPos)) so->markItemIndex = so->currPos.itemIndex; @@ -485,11 +485,11 @@ btrestrpos(PG_FUNCTION_ARGS) if (so->markItemIndex >= 0) { /* - * The mark position is on the same page we are currently on. - * Just restore the itemIndex. + * The mark position is on the same page we are currently on. Just + * restore the itemIndex. */ so->currPos.itemIndex = so->markItemIndex; - } + } else { /* we aren't holding any read locks, but gotta drop the pin */ @@ -527,7 +527,7 @@ Datum btbulkdelete(PG_FUNCTION_ARGS) { IndexVacuumInfo *info = (IndexVacuumInfo *) PG_GETARG_POINTER(0); - IndexBulkDeleteResult * volatile stats = (IndexBulkDeleteResult *) PG_GETARG_POINTER(1); + IndexBulkDeleteResult *volatile stats = (IndexBulkDeleteResult *) PG_GETARG_POINTER(1); IndexBulkDeleteCallback callback = (IndexBulkDeleteCallback) PG_GETARG_POINTER(2); void *callback_state = (void *) PG_GETARG_POINTER(3); Relation rel = info->index; @@ -569,10 +569,10 @@ btvacuumcleanup(PG_FUNCTION_ARGS) IndexBulkDeleteResult *stats = (IndexBulkDeleteResult *) PG_GETARG_POINTER(1); /* - * If btbulkdelete was called, we need not do anything, just return - * the stats from the latest btbulkdelete call. If it wasn't called, - * we must still do a pass over the index, to recycle any newly-recyclable - * pages and to obtain index statistics. + * If btbulkdelete was called, we need not do anything, just return the + * stats from the latest btbulkdelete call. If it wasn't called, we must + * still do a pass over the index, to recycle any newly-recyclable pages + * and to obtain index statistics. * * Since we aren't going to actually delete any leaf items, there's no * need to go through all the vacuum-cycle-ID pushups. @@ -586,8 +586,8 @@ btvacuumcleanup(PG_FUNCTION_ARGS) /* * During a non-FULL vacuum it's quite possible for us to be fooled by * concurrent page splits into double-counting some index tuples, so - * disbelieve any total that exceeds the underlying heap's count. - * (We can't check this during btbulkdelete.) + * disbelieve any total that exceeds the underlying heap's count. (We + * can't check this during btbulkdelete.) */ if (!info->vacuum_full) { @@ -622,8 +622,8 @@ btvacuumscan(IndexVacuumInfo *info, IndexBulkDeleteResult *stats, bool needLock; /* - * Reset counts that will be incremented during the scan; needed in - * case of multiple scans during a single VACUUM command + * Reset counts that will be incremented during the scan; needed in case + * of multiple scans during a single VACUUM command */ stats->num_index_tuples = 0; stats->pages_deleted = 0; @@ -647,24 +647,24 @@ btvacuumscan(IndexVacuumInfo *info, IndexBulkDeleteResult *stats, ALLOCSET_DEFAULT_MAXSIZE); /* - * The outer loop iterates over all index pages except the metapage, - * in physical order (we hope the kernel will cooperate in providing + * The outer loop iterates over all index pages except the metapage, in + * physical order (we hope the kernel will cooperate in providing * read-ahead for speed). It is critical that we visit all leaf pages, * including ones added after we start the scan, else we might fail to * delete some deletable tuples. Hence, we must repeatedly check the * relation length. We must acquire the relation-extension lock while * doing so to avoid a race condition: if someone else is extending the * relation, there is a window where bufmgr/smgr have created a new - * all-zero page but it hasn't yet been write-locked by _bt_getbuf(). - * If we manage to scan such a page here, we'll improperly assume it can - * be recycled. Taking the lock synchronizes things enough to prevent a + * all-zero page but it hasn't yet been write-locked by _bt_getbuf(). If + * we manage to scan such a page here, we'll improperly assume it can be + * recycled. Taking the lock synchronizes things enough to prevent a * problem: either num_pages won't include the new page, or _bt_getbuf * already has write lock on the buffer and it will be fully initialized * before we can examine it. (See also vacuumlazy.c, which has the same - * issue.) Also, we need not worry if a page is added immediately after + * issue.) Also, we need not worry if a page is added immediately after * we look; the page splitting code already has write-lock on the left - * page before it adds a right page, so we must already have processed - * any tuples due to be moved into such a page. + * page before it adds a right page, so we must already have processed any + * tuples due to be moved into such a page. * * We can skip locking for new or temp relations, however, since no one * else could be accessing them. @@ -771,7 +771,7 @@ btvacuumpage(BTVacState *vstate, BlockNumber blkno, BlockNumber orig_blkno) void *callback_state = vstate->callback_state; Relation rel = info->index; bool delete_now; - BlockNumber recurse_to; + BlockNumber recurse_to; Buffer buf; Page page; BTPageOpaque opaque; @@ -796,10 +796,10 @@ restart: _bt_checkpage(rel, buf); /* - * If we are recursing, the only case we want to do anything with is - * a live leaf page having the current vacuum cycle ID. Any other state - * implies we already saw the page (eg, deleted it as being empty). - * In particular, we don't want to risk adding it to freePages twice. + * If we are recursing, the only case we want to do anything with is a + * live leaf page having the current vacuum cycle ID. Any other state + * implies we already saw the page (eg, deleted it as being empty). In + * particular, we don't want to risk adding it to freePages twice. */ if (blkno != orig_blkno) { @@ -838,25 +838,24 @@ restart: OffsetNumber deletable[MaxOffsetNumber]; int ndeletable; OffsetNumber offnum, - minoff, - maxoff; + minoff, + maxoff; /* - * Trade in the initial read lock for a super-exclusive write - * lock on this page. We must get such a lock on every leaf page - * over the course of the vacuum scan, whether or not it actually - * contains any deletable tuples --- see nbtree/README. + * Trade in the initial read lock for a super-exclusive write lock on + * this page. We must get such a lock on every leaf page over the + * course of the vacuum scan, whether or not it actually contains any + * deletable tuples --- see nbtree/README. */ LockBuffer(buf, BUFFER_LOCK_UNLOCK); LockBufferForCleanup(buf); /* - * Check whether we need to recurse back to earlier pages. What - * we are concerned about is a page split that happened since we - * started the vacuum scan. If the split moved some tuples to a - * lower page then we might have missed 'em. If so, set up for - * tail recursion. (Must do this before possibly clearing - * btpo_cycleid below!) + * Check whether we need to recurse back to earlier pages. What we + * are concerned about is a page split that happened since we started + * the vacuum scan. If the split moved some tuples to a lower page + * then we might have missed 'em. If so, set up for tail recursion. + * (Must do this before possibly clearing btpo_cycleid below!) */ if (vstate->cycleid != 0 && opaque->btpo_cycleid == vstate->cycleid && @@ -866,8 +865,8 @@ restart: recurse_to = opaque->btpo_next; /* - * Scan over all items to see which ones need deleted - * according to the callback function. + * Scan over all items to see which ones need deleted according to the + * callback function. */ ndeletable = 0; minoff = P_FIRSTDATAKEY(opaque); @@ -890,8 +889,8 @@ restart: } /* - * Apply any needed deletes. We issue just one _bt_delitems() - * call per page, so as to minimize WAL traffic. + * Apply any needed deletes. We issue just one _bt_delitems() call + * per page, so as to minimize WAL traffic. */ if (ndeletable > 0) { @@ -908,8 +907,8 @@ restart: * have any deletions to do. (If we do, _bt_delitems takes care * of this.) This ensures we won't process the page again. * - * We treat this like a hint-bit update because there's no need - * to WAL-log it. + * We treat this like a hint-bit update because there's no need to + * WAL-log it. */ if (vstate->cycleid != 0 && opaque->btpo_cycleid == vstate->cycleid) @@ -920,10 +919,10 @@ restart: } /* - * If it's now empty, try to delete; else count the live tuples. - * We don't delete when recursing, though, to avoid putting entries - * into freePages out-of-order (doesn't seem worth any extra code to - * handle the case). + * If it's now empty, try to delete; else count the live tuples. We + * don't delete when recursing, though, to avoid putting entries into + * freePages out-of-order (doesn't seem worth any extra code to handle + * the case). */ if (minoff > maxoff) delete_now = (blkno == orig_blkno); @@ -947,13 +946,12 @@ restart: stats->pages_deleted++; /* - * During VACUUM FULL it's okay to recycle deleted pages - * immediately, since there can be no other transactions scanning - * the index. Note that we will only recycle the current page and - * not any parent pages that _bt_pagedel might have recursed to; - * this seems reasonable in the name of simplicity. (Trying to do - * otherwise would mean we'd have to sort the list of recyclable - * pages we're building.) + * During VACUUM FULL it's okay to recycle deleted pages immediately, + * since there can be no other transactions scanning the index. Note + * that we will only recycle the current page and not any parent pages + * that _bt_pagedel might have recursed to; this seems reasonable in + * the name of simplicity. (Trying to do otherwise would mean we'd + * have to sort the list of recyclable pages we're building.) */ if (ndel && info->vacuum_full) { @@ -969,11 +967,11 @@ restart: _bt_relbuf(rel, buf); /* - * This is really tail recursion, but if the compiler is too stupid - * to optimize it as such, we'd eat an uncomfortably large amount of - * stack space per recursion level (due to the deletable[] array). - * A failure is improbable since the number of levels isn't likely to be - * large ... but just in case, let's hand-optimize into a loop. + * This is really tail recursion, but if the compiler is too stupid to + * optimize it as such, we'd eat an uncomfortably large amount of stack + * space per recursion level (due to the deletable[] array). A failure is + * improbable since the number of levels isn't likely to be large ... but + * just in case, let's hand-optimize into a loop. */ if (recurse_to != P_NONE) { |