diff options
Diffstat (limited to 'src/backend/executor/nodeIndexscan.c')
| -rw-r--r-- | src/backend/executor/nodeIndexscan.c | 42 |
1 files changed, 34 insertions, 8 deletions
diff --git a/src/backend/executor/nodeIndexscan.c b/src/backend/executor/nodeIndexscan.c index cdf13c5e19e..16bb4f23b41 100644 --- a/src/backend/executor/nodeIndexscan.c +++ b/src/backend/executor/nodeIndexscan.c @@ -7,7 +7,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/executor/nodeIndexscan.c,v 1.33 1999/02/21 03:48:40 scrappy Exp $ + * $Header: /cvsroot/pgsql/src/backend/executor/nodeIndexscan.c,v 1.34 1999/04/13 17:18:29 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -96,6 +96,8 @@ IndexNext(IndexScan *node) Buffer buffer = InvalidBuffer; int numIndices; + bool bBackward; + int indexNumber; /* ---------------- * extract necessary information from index scan node * ---------------- @@ -151,8 +153,26 @@ IndexNext(IndexScan *node) * appropriate heap tuple.. else return NULL. * ---------------- */ - while (indexstate->iss_IndexPtr < numIndices) - { + bBackward = ScanDirectionIsBackward(direction); + if (bBackward) + { + indexNumber = numIndices - indexstate->iss_IndexPtr - 1; + if (indexNumber < 0) + { + indexNumber = 0; + indexstate->iss_IndexPtr = numIndices - 1; + } + } + else + { + if ((indexNumber = indexstate->iss_IndexPtr) < 0) + { + indexNumber = 0; + indexstate->iss_IndexPtr = 0; + } + } + while (indexNumber < numIndices) + { scandesc = scanDescs[indexstate->iss_IndexPtr]; while ((result = index_getnext(scandesc, direction)) != NULL) { @@ -204,8 +224,14 @@ IndexNext(IndexScan *node) if (BufferIsValid(buffer)) ReleaseBuffer(buffer); } - if (indexstate->iss_IndexPtr < numIndices) - indexstate->iss_IndexPtr++; + if (indexNumber < numIndices) + { + indexNumber++; + if (bBackward) + indexstate->iss_IndexPtr--; + else + indexstate->iss_IndexPtr++; + } } /* ---------------- * if we get here it means the index scan failed so we @@ -294,7 +320,7 @@ ExecIndexReScan(IndexScan *node, ExprContext *exprCtxt, Plan *parent) runtimeKeyInfo = (Pointer *) indexstate->iss_RuntimeKeyInfo; indxqual = node->indxqual; numScanKeys = indexstate->iss_NumScanKeys; - indexstate->iss_IndexPtr = 0; + indexstate->iss_IndexPtr = -1; /* If this is re-scanning of PlanQual ... */ if (estate->es_evTuple != NULL && @@ -611,7 +637,7 @@ ExecInitIndexScan(IndexScan *node, EState *estate, Plan *parent) */ indexstate = makeNode(IndexScanState); indexstate->iss_NumIndices = 0; - indexstate->iss_IndexPtr = 0; + indexstate->iss_IndexPtr = -1; indexstate->iss_ScanKeys = NULL; indexstate->iss_NumScanKeys = NULL; indexstate->iss_RuntimeKeyInfo = NULL; @@ -635,7 +661,7 @@ ExecInitIndexScan(IndexScan *node, EState *estate, Plan *parent) indxid = node->indxid; indxqual = node->indxqual; numIndices = length(indxid); - indexPtr = 0; + indexPtr = -1; CXT1_printf("ExecInitIndexScan: context is %d\n", CurrentMemoryContext); |