diff options
Diffstat (limited to 'src/backend/executor/nodeBitmapHeapscan.c')
| -rw-r--r-- | src/backend/executor/nodeBitmapHeapscan.c | 69 |
1 files changed, 34 insertions, 35 deletions
diff --git a/src/backend/executor/nodeBitmapHeapscan.c b/src/backend/executor/nodeBitmapHeapscan.c index 3c3c1fd96f1..5d92c19ea5e 100644 --- a/src/backend/executor/nodeBitmapHeapscan.c +++ b/src/backend/executor/nodeBitmapHeapscan.c @@ -5,7 +5,7 @@ * * NOTE: it is critical that this plan type only be used with MVCC-compliant * snapshots (ie, regular snapshots, not SnapshotNow or one of the other - * special snapshots). The reason is that since index and heap scans are + * special snapshots). The reason is that since index and heap scans are * decoupled, there can be no assurance that the index tuple prompting a * visit to a particular heap TID still exists when the visit is made. * Therefore the tuple might not exist anymore either (which is OK because @@ -21,7 +21,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/nodeBitmapHeapscan.c,v 1.3 2005/10/06 02:29:16 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/executor/nodeBitmapHeapscan.c,v 1.4 2005/10/15 02:49:17 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -76,11 +76,11 @@ BitmapHeapNext(BitmapHeapScanState *node) tbmres = node->tbmres; /* - * Clear any reference to the previously returned tuple. The idea - * here is to not have the tuple slot be the last holder of a pin on - * that tuple's buffer; if it is, we'll need a separate visit to the - * bufmgr to release the buffer. By clearing here, we get to have the - * release done by ReleaseAndReadBuffer, below. + * Clear any reference to the previously returned tuple. The idea here is + * to not have the tuple slot be the last holder of a pin on that tuple's + * buffer; if it is, we'll need a separate visit to the bufmgr to release + * the buffer. By clearing here, we get to have the release done by + * ReleaseAndReadBuffer, below. */ ExecClearTuple(slot); @@ -105,7 +105,7 @@ BitmapHeapNext(BitmapHeapScanState *node) ResetExprContext(econtext); if (!ExecQual(node->bitmapqualorig, econtext, false)) - ExecClearTuple(slot); /* would not be returned by scan */ + ExecClearTuple(slot); /* would not be returned by scan */ /* Flag for the next call that no more tuples */ estate->es_evTupleNull[scanrelid - 1] = true; @@ -114,8 +114,8 @@ BitmapHeapNext(BitmapHeapScanState *node) } /* - * If we haven't yet performed the underlying index scan, do it, - * and prepare the bitmap to be iterated over. + * If we haven't yet performed the underlying index scan, do it, and + * prepare the bitmap to be iterated over. */ if (tbm == NULL) { @@ -145,10 +145,10 @@ BitmapHeapNext(BitmapHeapScanState *node) } /* - * Ignore any claimed entries past what we think is the end of - * the relation. (This is probably not necessary given that we - * got AccessShareLock before performing any of the indexscans, - * but let's be safe.) + * Ignore any claimed entries past what we think is the end of the + * relation. (This is probably not necessary given that we got + * AccessShareLock before performing any of the indexscans, but + * let's be safe.) */ if (tbmres->blockno >= scandesc->rs_nblocks) { @@ -157,19 +157,18 @@ BitmapHeapNext(BitmapHeapScanState *node) } /* - * Acquire pin on the current heap page. We'll hold the pin - * until done looking at the page. We trade in any pin we - * held before. + * Acquire pin on the current heap page. We'll hold the pin until + * done looking at the page. We trade in any pin we held before. */ scandesc->rs_cbuf = ReleaseAndReadBuffer(scandesc->rs_cbuf, scandesc->rs_rd, tbmres->blockno); /* - * Determine how many entries we need to look at on this page. - * If the bitmap is lossy then we need to look at each physical - * item pointer; otherwise we just look through the offsets - * listed in tbmres. + * Determine how many entries we need to look at on this page. If + * the bitmap is lossy then we need to look at each physical item + * pointer; otherwise we just look through the offsets listed in + * tbmres. */ if (tbmres->ntuples >= 0) { @@ -180,7 +179,7 @@ BitmapHeapNext(BitmapHeapScanState *node) else { /* lossy case */ - Page dp; + Page dp; LockBuffer(scandesc->rs_cbuf, BUFFER_LOCK_SHARE); dp = (Page) BufferGetPage(scandesc->rs_cbuf); @@ -230,8 +229,8 @@ BitmapHeapNext(BitmapHeapScanState *node) ItemPointerSet(&scandesc->rs_ctup.t_self, tbmres->blockno, targoffset); /* - * Fetch the heap tuple and see if it matches the snapshot. - * We use heap_release_fetch to avoid useless bufmgr traffic. + * Fetch the heap tuple and see if it matches the snapshot. We use + * heap_release_fetch to avoid useless bufmgr traffic. */ if (heap_release_fetch(scandesc->rs_rd, scandesc->rs_snapshot, @@ -241,8 +240,8 @@ BitmapHeapNext(BitmapHeapScanState *node) &scandesc->rs_pgstat_info)) { /* - * Set up the result slot to point to this tuple. - * Note that the slot acquires a pin on the buffer. + * Set up the result slot to point to this tuple. Note that the + * slot acquires a pin on the buffer. */ ExecStoreTuple(&scandesc->rs_ctup, slot, @@ -338,8 +337,8 @@ ExecBitmapHeapReScan(BitmapHeapScanState *node, ExprContext *exprCtxt) node->tbmres = NULL; /* - * Always rescan the input immediately, to ensure we can pass down - * any outer tuple that might be used in index quals. + * Always rescan the input immediately, to ensure we can pass down any + * outer tuple that might be used in index quals. */ ExecReScan(outerPlanState(node), exprCtxt); } @@ -391,9 +390,9 @@ ExecEndBitmapHeapScan(BitmapHeapScanState *node) * close the heap relation. * * Currently, we do not release the AccessShareLock acquired by - * ExecInitBitmapHeapScan. This lock should be held till end of - * transaction. (There is a faction that considers this too much - * locking, however.) + * ExecInitBitmapHeapScan. This lock should be held till end of + * transaction. (There is a faction that considers this too much locking, + * however.) */ heap_close(relation, NoLock); } @@ -470,9 +469,9 @@ ExecInitBitmapHeapScan(BitmapHeapScan *node, EState *estate) scanstate->ss.ss_currentRelation = currentRelation; /* - * Even though we aren't going to do a conventional seqscan, it is - * useful to create a HeapScanDesc --- this checks the relation size - * and sets up statistical infrastructure for us. + * Even though we aren't going to do a conventional seqscan, it is useful + * to create a HeapScanDesc --- this checks the relation size and sets up + * statistical infrastructure for us. */ scanstate->ss.ss_currentScanDesc = heap_beginscan(currentRelation, estate->es_snapshot, @@ -482,7 +481,7 @@ ExecInitBitmapHeapScan(BitmapHeapScan *node, EState *estate) /* * One problem is that heap_beginscan counts a "sequential scan" start, * when we actually aren't doing any such thing. Reverse out the added - * scan count. (Eventually we may want to count bitmap scans separately.) + * scan count. (Eventually we may want to count bitmap scans separately.) */ pgstat_discount_heap_scan(&scanstate->ss.ss_currentScanDesc->rs_pgstat_info); |