diff options
Diffstat (limited to 'src/backend/access/index/indexam.c')
| -rw-r--r-- | src/backend/access/index/indexam.c | 174 |
1 files changed, 126 insertions, 48 deletions
diff --git a/src/backend/access/index/indexam.c b/src/backend/access/index/indexam.c index ce2c8e62f45..b616212bb50 100644 --- a/src/backend/access/index/indexam.c +++ b/src/backend/access/index/indexam.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/access/index/indexam.c,v 1.57 2002/04/17 20:57:56 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/access/index/indexam.c,v 1.58 2002/05/20 23:51:41 tgl Exp $ * * INTERFACE ROUTINES * index_open - open an index relation by relation OID @@ -73,20 +73,20 @@ */ #define RELATION_CHECKS \ ( \ - AssertMacro(RelationIsValid(relation)), \ - AssertMacro(PointerIsValid(relation->rd_am)) \ + AssertMacro(RelationIsValid(indexRelation)), \ + AssertMacro(PointerIsValid(indexRelation->rd_am)) \ ) #define SCAN_CHECKS \ ( \ AssertMacro(IndexScanIsValid(scan)), \ - AssertMacro(RelationIsValid(scan->relation)), \ - AssertMacro(PointerIsValid(scan->relation->rd_am)) \ + AssertMacro(RelationIsValid(scan->indexRelation)), \ + AssertMacro(PointerIsValid(scan->indexRelation->rd_am)) \ ) #define GET_REL_PROCEDURE(x,y) \ ( \ - procedure = relation->rd_am->y, \ + procedure = indexRelation->rd_am->y, \ (!RegProcedureIsValid(procedure)) ? \ elog(ERROR, "index_%s: invalid %s regproc", \ CppAsString(x), CppAsString(y)) \ @@ -95,7 +95,7 @@ #define GET_SCAN_PROCEDURE(x,y) \ ( \ - procedure = scan->relation->rd_am->y, \ + procedure = scan->indexRelation->rd_am->y, \ (!RegProcedureIsValid(procedure)) ? \ elog(ERROR, "index_%s: invalid %s regproc", \ CppAsString(x), CppAsString(y)) \ @@ -200,11 +200,11 @@ index_close(Relation relation) * ---------------- */ InsertIndexResult -index_insert(Relation relation, - Datum *datum, +index_insert(Relation indexRelation, + Datum *datums, char *nulls, ItemPointer heap_t_ctid, - Relation heapRel) + Relation heapRelation) { RegProcedure procedure; InsertIndexResult specificResult; @@ -217,11 +217,11 @@ index_insert(Relation relation, */ specificResult = (InsertIndexResult) DatumGetPointer(OidFunctionCall5(procedure, - PointerGetDatum(relation), - PointerGetDatum(datum), + PointerGetDatum(indexRelation), + PointerGetDatum(datums), PointerGetDatum(nulls), PointerGetDatum(heap_t_ctid), - PointerGetDatum(heapRel))); + PointerGetDatum(heapRelation))); /* must be pfree'ed */ return specificResult; @@ -229,13 +229,19 @@ index_insert(Relation relation, /* ---------------- * index_beginscan - start a scan of an index + * + * Note: heapRelation may be NULL if there is no intention of calling + * index_getnext on this scan; index_getnext_indexitem will not use the + * heapRelation link (nor the snapshot). However, the caller had better + * be holding some kind of lock on the heap relation in any case, to ensure + * no one deletes it (or the index) out from under us. * ---------------- */ IndexScanDesc -index_beginscan(Relation relation, - bool scanFromEnd, - uint16 numberOfKeys, - ScanKey key) +index_beginscan(Relation heapRelation, + Relation indexRelation, + Snapshot snapshot, + int nkeys, ScanKey key) { IndexScanDesc scan; RegProcedure procedure; @@ -243,7 +249,7 @@ index_beginscan(Relation relation, RELATION_CHECKS; GET_REL_PROCEDURE(beginscan, ambeginscan); - RelationIncrementReferenceCount(relation); + RelationIncrementReferenceCount(indexRelation); /* * Acquire AccessShareLock for the duration of the scan @@ -252,16 +258,23 @@ index_beginscan(Relation relation, * rebuild the relcache entry. The refcount increment above ensures * that we will rebuild it and not just flush it... */ - LockRelation(relation, AccessShareLock); + LockRelation(indexRelation, AccessShareLock); + /* + * Tell the AM to open a scan. + */ scan = (IndexScanDesc) - DatumGetPointer(OidFunctionCall4(procedure, - PointerGetDatum(relation), - BoolGetDatum(scanFromEnd), - UInt16GetDatum(numberOfKeys), + DatumGetPointer(OidFunctionCall3(procedure, + PointerGetDatum(indexRelation), + Int32GetDatum(nkeys), PointerGetDatum(key))); - pgstat_initstats(&scan->xs_pgstat_info, relation); + /* + * Save additional parameters into the scandesc. Everything else + * was set up by RelationGetIndexScan. + */ + scan->heapRelation = heapRelation; + scan->xs_snapshot = snapshot; /* * We want to look up the amgettuple procedure just once per scan, not @@ -275,20 +288,23 @@ index_beginscan(Relation relation, } /* ---------------- - * index_rescan - restart a scan of an index + * index_rescan - (re)start a scan of an index + * + * The caller may specify a new set of scankeys (but the number of keys + * cannot change). Note that this is also called when first starting + * an indexscan; see RelationGetIndexScan. * ---------------- */ void -index_rescan(IndexScanDesc scan, bool scanFromEnd, ScanKey key) +index_rescan(IndexScanDesc scan, ScanKey key) { RegProcedure procedure; SCAN_CHECKS; GET_SCAN_PROCEDURE(rescan, amrescan); - OidFunctionCall3(procedure, + OidFunctionCall2(procedure, PointerGetDatum(scan), - BoolGetDatum(scanFromEnd), PointerGetDatum(key)); pgstat_reset_index_scan(&scan->xs_pgstat_info); @@ -306,13 +322,21 @@ index_endscan(IndexScanDesc scan) SCAN_CHECKS; GET_SCAN_PROCEDURE(endscan, amendscan); + /* Release any held pin on a heap page */ + if (BufferIsValid(scan->xs_cbuf)) + { + ReleaseBuffer(scan->xs_cbuf); + scan->xs_cbuf = InvalidBuffer; + } + + /* End the AM's scan */ OidFunctionCall1(procedure, PointerGetDatum(scan)); - /* Release lock and refcount acquired by index_beginscan */ + /* Release index lock and refcount acquired by index_beginscan */ - UnlockRelation(scan->relation, AccessShareLock); + UnlockRelation(scan->indexRelation, AccessShareLock); - RelationDecrementReferenceCount(scan->relation); + RelationDecrementReferenceCount(scan->indexRelation); /* Release the scan data structure itself */ IndexScanEnd(scan); @@ -349,33 +373,87 @@ index_restrpos(IndexScanDesc scan) } /* ---------------- - * index_getnext - get the next tuple from a scan + * index_getnext - get the next heap tuple from a scan * - * A RetrieveIndexResult is a index tuple/heap tuple pair + * The result is the next heap tuple satisfying the scan keys and the + * snapshot, or NULL if no more matching tuples exist. On success, + * the buffer containing the heap tuple is pinned (the pin will be dropped + * at the next index_getnext or index_endscan). The index TID corresponding + * to the heap tuple can be obtained if needed from scan->currentItemData. * ---------------- */ -RetrieveIndexResult -index_getnext(IndexScanDesc scan, - ScanDirection direction) +HeapTuple +index_getnext(IndexScanDesc scan, ScanDirection direction) { - RetrieveIndexResult result; + bool found; SCAN_CHECKS; - pgstat_count_index_scan(&scan->xs_pgstat_info); + /* Release any previously held pin */ + if (BufferIsValid(scan->xs_cbuf)) + { + ReleaseBuffer(scan->xs_cbuf); + scan->xs_cbuf = InvalidBuffer; + } + + for (;;) + { + pgstat_count_index_scan(&scan->xs_pgstat_info); + + /* + * The AM's gettuple proc finds the next tuple matching the scan + * keys. index_beginscan already set up fn_getnext. + */ + found = DatumGetBool(FunctionCall2(&scan->fn_getnext, + PointerGetDatum(scan), + Int32GetDatum(direction))); + if (!found) + return NULL; /* failure exit */ + /* + * Fetch the heap tuple and see if it matches the snapshot. + */ + heap_fetch(scan->heapRelation, scan->xs_snapshot, + &scan->xs_ctup, &scan->xs_cbuf, + &scan->xs_pgstat_info); + if (scan->xs_ctup.t_data != NULL) + break; + /* + * XXX here, consider whether we can kill the index tuple. + */ + } + + /* Success exit */ + pgstat_count_index_getnext(&scan->xs_pgstat_info); + + return &scan->xs_ctup; +} + +/* ---------------- + * index_getnext_indexitem - get the next index tuple from a scan + * + * Finds the next index tuple satisfying the scan keys. Note that no + * time qual (snapshot) check is done; indeed the heap tuple is not accessed. + * On success (TRUE return), the found index TID is in scan->currentItemData, + * and its heap TID is in scan->xs_ctup.t_self. scan->xs_cbuf is untouched. + * ---------------- + */ +bool +index_getnext_indexitem(IndexScanDesc scan, + ScanDirection direction) +{ + bool found; + + SCAN_CHECKS; /* * have the am's gettuple proc do all the work. index_beginscan * already set up fn_getnext. */ - result = (RetrieveIndexResult) - DatumGetPointer(FunctionCall2(&scan->fn_getnext, - PointerGetDatum(scan), - Int32GetDatum(direction))); + found = DatumGetBool(FunctionCall2(&scan->fn_getnext, + PointerGetDatum(scan), + Int32GetDatum(direction))); - if (result != NULL) - pgstat_count_index_getnext(&scan->xs_pgstat_info); - return result; + return found; } /* ---------------- @@ -388,7 +466,7 @@ index_getnext(IndexScanDesc scan, * ---------------- */ IndexBulkDeleteResult * -index_bulk_delete(Relation relation, +index_bulk_delete(Relation indexRelation, IndexBulkDeleteCallback callback, void *callback_state) { @@ -400,7 +478,7 @@ index_bulk_delete(Relation relation, result = (IndexBulkDeleteResult *) DatumGetPointer(OidFunctionCall3(procedure, - PointerGetDatum(relation), + PointerGetDatum(indexRelation), PointerGetDatum((Pointer) callback), PointerGetDatum(callback_state))); @@ -418,7 +496,7 @@ index_bulk_delete(Relation relation, * ---------------- */ RegProcedure -index_cost_estimator(Relation relation) +index_cost_estimator(Relation indexRelation) { RegProcedure procedure; |