diff options
Diffstat (limited to 'src/backend/access/nbtree/nbtsearch.c')
| -rw-r--r-- | src/backend/access/nbtree/nbtsearch.c | 72 |
1 files changed, 60 insertions, 12 deletions
diff --git a/src/backend/access/nbtree/nbtsearch.c b/src/backend/access/nbtree/nbtsearch.c index 593a5453bc5..1ea080abd72 100644 --- a/src/backend/access/nbtree/nbtsearch.c +++ b/src/backend/access/nbtree/nbtsearch.c @@ -7,7 +7,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtsearch.c,v 1.42 1999/03/28 20:31:58 vadim Exp $ + * $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtsearch.c,v 1.43 1999/04/13 17:18:28 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -733,7 +733,8 @@ _bt_next(IndexScanDesc scan, ScanDirection dir) return res; } - } while (keysok >= so->numberOfFirstKeys); + } while (keysok >= so->numberOfFirstKeys || + (keysok == -1 && ScanDirectionIsBackward(dir))); ItemPointerSetInvalid(current); so->btso_curbuf = InvalidBuffer; @@ -775,6 +776,8 @@ _bt_first(IndexScanDesc scan, ScanDirection dir) BTScanOpaque so; ScanKeyData skdata; Size keysok; + int i; + int nKeyIndex = -1; rel = scan->relation; so = (BTScanOpaque) scan->opaque; @@ -790,11 +793,34 @@ _bt_first(IndexScanDesc scan, ScanDirection dir) { _bt_orderkeys(rel, so); - strat = _bt_getstrat(rel, 1, so->keyData[0].sk_procedure); + if (ScanDirectionIsBackward(dir)) + { + for (i=0; i<so->numberOfKeys; i++) + { + if (so->keyData[i].sk_attno != 1) + break; + strat = _bt_getstrat(rel, so->keyData[i].sk_attno, + so->keyData[i].sk_procedure); + if (strat == BTLessStrategyNumber || + strat == BTLessEqualStrategyNumber|| + strat == BTEqualStrategyNumber) + { + nKeyIndex = i; + break; + } + } + } + else + { + strat = _bt_getstrat(rel, 1, so->keyData[0].sk_procedure); - /* NOTE: it assumes ForwardScanDirection */ - if (strat == BTLessStrategyNumber || - strat == BTLessEqualStrategyNumber) + if (strat == BTLessStrategyNumber || + strat == BTLessEqualStrategyNumber) + ; + else + nKeyIndex = 0; + } + if (nKeyIndex < 0) scan->scanFromEnd = true; } else @@ -823,8 +849,8 @@ _bt_first(IndexScanDesc scan, ScanDirection dir) return (RetrieveIndexResult) NULL; } proc = index_getprocid(rel, 1, BTORDER_PROC); - ScanKeyEntryInitialize(&skdata, so->keyData[0].sk_flags, 1, proc, - so->keyData[0].sk_argument); + ScanKeyEntryInitialize(&skdata, so->keyData[nKeyIndex].sk_flags, + 1, proc, so->keyData[nKeyIndex].sk_argument); stack = _bt_search(rel, 1, &skdata, &buf); _bt_freestack(stack); @@ -897,7 +923,7 @@ _bt_first(IndexScanDesc scan, ScanDirection dir) /* it's yet other place to add some code latter for is(not)null */ - strat = _bt_getstrat(rel, 1, so->keyData[0].sk_procedure); + strat = _bt_getstrat(rel, 1, so->keyData[nKeyIndex].sk_procedure); switch (strat) { @@ -914,9 +940,6 @@ _bt_first(IndexScanDesc scan, ScanDirection dir) result = _bt_compare(rel, itupdesc, page, 1, &skdata, offnum); } while (result <= 0); - /* if this is true, the key we just looked at is gone */ - if (result > 0) - _bt_twostep(scan, &buf, ForwardScanDirection); } break; @@ -946,6 +969,21 @@ _bt_first(IndexScanDesc scan, ScanDirection dir) ItemPointerSetInvalid(&(scan->currentItemData)); return (RetrieveIndexResult) NULL; } + else if (ScanDirectionIsBackward(dir)) + { + do + { + if (!_bt_twostep(scan, &buf, ForwardScanDirection)) + break; + + offnum = ItemPointerGetOffsetNumber(current); + page = BufferGetPage(buf); + result = _bt_compare(rel, itupdesc, page, 1, &skdata, offnum); + } while (result == 0); + + if (result < 0) + _bt_twostep(scan, &buf, BackwardScanDirection); + } break; case BTGreaterEqualStrategyNumber: @@ -1026,6 +1064,11 @@ _bt_first(IndexScanDesc scan, ScanDirection dir) so->btso_curbuf = buf; return _bt_next(scan, dir); } + else if (keysok == -1 && ScanDirectionIsBackward(dir)) + { + so->btso_curbuf = buf; + return _bt_next(scan, dir); + } else { ItemPointerSetInvalid(current); @@ -1495,6 +1538,11 @@ _bt_endpoint(IndexScanDesc scan, ScanDirection dir) so->btso_curbuf = buf; return _bt_next(scan, dir); } + else if (keysok == -1 && ScanDirectionIsBackward(dir)) + { + so->btso_curbuf = buf; + return _bt_next(scan, dir); + } else { ItemPointerSetInvalid(current); |