/*------------------------------------------------------------------------- * * indexam.c-- * general index access method routines * * Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $Header: /usr/local/cvsroot/pgsql/src/backend/access/index/indexam.c,v 1.17 1997/09/12 04:07:15 momjian Exp $ * * INTERFACE ROUTINES * index_open - open an index relation by relationId * index_openr - open a index relation by name * index_close - close a index relation * index_beginscan - start a scan of an index * index_rescan - restart a scan of an index * index_endscan - end a scan * index_insert - insert an index tuple into a relation * index_delete - delete an item from an index relation * index_markpos - mark a scan position * index_restrpos - restore a scan position * index_getnext - get the next tuple from a scan * ** index_fetch - retrieve tuple with tid * ** index_replace - replace a tuple * ** index_getattr - get an attribute from an index tuple * index_getprocid - get a support procedure id from the rel tuple * * IndexScanIsValid - check index scan * * NOTES * This file contains the index_ routines which used * to be a scattered collection of stuff in access/genam. * * The ** routines: index_fetch, index_replace, and index_getattr * have not yet been implemented. They may not be needed. * * old comments * Scans are implemented as follows: * * `0' represents an invalid item pointer. * `-' represents an unknown item pointer. * `X' represents a known item pointers. * `+' represents known or invalid item pointers. * `*' represents any item pointers. * * State is represented by a triple of these symbols in the order of * previous, current, next. Note that the case of reverse scans works * identically. * * State Result * (1) + + - + 0 0 (if the next item pointer is invalid) * (2) + X - (otherwise) * (3) * 0 0 * 0 0 (no change) * (4) + X 0 X 0 0 (shift) * (5) * + X + X - (shift, add unknown) * * All other states cannot occur. * * Note: It would be possible to cache the status of the previous and * next item pointer using the flags. * *------------------------------------------------------------------------- */ #include #include #include #include #include #include /* ---------------- * undefine macros we aren't going to use that would otherwise * get in our way.. delete is defined in c.h and the am's are * defined in heapam.h * ---------------- */ #undef delete #undef aminsert #undef amdelete #undef ambeginscan #undef amrescan #undef amendscan #undef ammarkpos #undef amrestrpos #undef amgettuple /* ---------------------------------------------------------------- * macros used in index_ routines * ---------------------------------------------------------------- */ #define RELATION_CHECKS \ Assert(RelationIsValid(relation)); \ Assert(PointerIsValid(relation->rd_am)) #define SCAN_CHECKS \ Assert(IndexScanIsValid(scan)); \ Assert(RelationIsValid(scan->relation)); \ Assert(PointerIsValid(scan->relation->rd_am)) #define GET_REL_PROCEDURE(x,y) \ procedure = relation->rd_am->y; \ if (! RegProcedureIsValid(procedure)) \ elog(WARN, "index_%s: invalid %s regproc", \ CppAsString(x), CppAsString(y)) #define GET_SCAN_PROCEDURE(x,y) \ procedure = scan->relation->rd_am->y; \ if (! RegProcedureIsValid(procedure)) \ elog(WARN, "index_%s: invalid %s regproc", \ CppAsString(x), CppAsString(y)) /* ---------------------------------------------------------------- * index_ interface functions * ---------------------------------------------------------------- */ /* ---------------- * index_open - open an index relation by relationId * * presently the relcache routines do all the work we need * to open/close index relations. * ---------------- */ Relation index_open(Oid relationId) { return RelationIdGetRelation(relationId); } /* ---------------- * index_openr - open a index relation by name * * presently the relcache routines do all the work we need * to open/close index relations. * ---------------- */ Relation index_openr(char *relationName) { return RelationNameGetRelation(relationName); } /* ---------------- * index_close - close a index relation * * presently the relcache routines do all the work we need * to open/close index relations. * ---------------- */ void index_close(Relation relation) { RelationClose(relation); } /* ---------------- * index_insert - insert an index tuple into a relation * ---------------- */ InsertIndexResult index_insert(Relation relation, Datum *datum, char *nulls, ItemPointer heap_t_ctid, Relation heapRel) { RegProcedure procedure; InsertIndexResult specificResult; RELATION_CHECKS; GET_REL_PROCEDURE(insert, aminsert); /* ---------------- * have the am's insert proc do all the work. * ---------------- */ specificResult = (InsertIndexResult) fmgr(procedure, relation, datum, nulls, heap_t_ctid, heapRel, NULL); /* ---------------- * the insert proc is supposed to return a "specific result" and * this routine has to return a "general result" so after we get * something back from the insert proc, we allocate a * "general result" and copy some crap between the two. * * As far as I'm concerned all this result shit is needlessly c * omplicated and should be eliminated. -cim 1/19/91 * * mao concurs. regardless of how we feel here, however, it is * important to free memory we don't intend to return to anyone. * 2/28/91 * * this "general result" crap is now gone. -ay 3/6/95 * ---------------- */ return (specificResult); } /* ---------------- * index_delete - delete an item from an index relation * ---------------- */ void index_delete(Relation relation, ItemPointer indexItem) { RegProcedure procedure; RELATION_CHECKS; GET_REL_PROCEDURE(delete, amdelete); fmgr(procedure, relation, indexItem); } /* ---------------- * index_beginscan - start a scan of an index * ---------------- */ IndexScanDesc index_beginscan(Relation relation, bool scanFromEnd, uint16 numberOfKeys, ScanKey key) { IndexScanDesc scandesc; RegProcedure procedure; RELATION_CHECKS; GET_REL_PROCEDURE(beginscan, ambeginscan); RelationSetRIntentLock(relation); scandesc = (IndexScanDesc) fmgr(procedure, relation, scanFromEnd, numberOfKeys, key); return scandesc; } /* ---------------- * index_rescan - restart a scan of an index * ---------------- */ void index_rescan(IndexScanDesc scan, bool scanFromEnd, ScanKey key) { RegProcedure procedure; SCAN_CHECKS; GET_SCAN_PROCEDURE(rescan, amrescan); fmgr(procedure, scan, scanFromEnd, key); } /* ---------------- * index_endscan - end a scan * ---------------- */ void index_endscan(IndexScanDesc scan) { RegProcedure procedure; SCAN_CHECKS; GET_SCAN_PROCEDURE(endscan, amendscan); fmgr(procedure, scan); RelationUnsetRIntentLock(scan->relation); } #ifdef NOT_USED /* ---------------- * index_markpos - mark a scan position * ---------------- */ void index_markpos(IndexScanDesc scan) { RegProcedure procedure; SCAN_CHECKS; GET_SCAN_PROCEDURE(markpos, ammarkpos); fmgr(procedure, scan); } #endif #ifdef NOT_USED /* ---------------- * index_restrpos - restore a scan position * ---------------- */ void index_restrpos(IndexScanDesc scan) { RegProcedure procedure; SCAN_CHECKS; GET_SCAN_PROCEDURE(restrpos, amrestrpos); fmgr(procedure, scan); } #endif /* ---------------- * index_getnext - get the next tuple from a scan * * A RetrieveIndexResult is a index tuple/heap tuple pair * ---------------- */ RetrieveIndexResult index_getnext(IndexScanDesc scan, ScanDirection direction) { RegProcedure procedure; RetrieveIndexResult result; SCAN_CHECKS; GET_SCAN_PROCEDURE(getnext, amgettuple); /* ---------------- * have the am's gettuple proc do all the work. * ---------------- */ result = (RetrieveIndexResult) fmgr(procedure, scan, direction); return result; } /* ---------------- * index_getprocid * * Some indexed access methods may require support routines that are * not in the operator class/operator model imposed by pg_am. These * access methods may store the OIDs of registered procedures they * need in pg_amproc. These registered procedure OIDs are ordered in * a way that makes sense to the access method, and used only by the * access method. The general index code doesn't know anything about * the routines involved; it just builds an ordered list of them for * each attribute on which an index is defined. * * This routine returns the requested procedure OID for a particular * indexed attribute. * ---------------- */ RegProcedure index_getprocid(Relation irel, AttrNumber attnum, uint16 procnum) { RegProcedure *loc; int natts; natts = irel->rd_rel->relnatts; loc = irel->rd_support; Assert(loc != NULL); return (loc[(natts * (procnum - 1)) + (attnum - 1)]); } Datum GetIndexValue(HeapTuple tuple, TupleDesc hTupDesc, int attOff, AttrNumber attrNums[], FuncIndexInfo *fInfo, bool *attNull, Buffer buffer) { Datum returnVal; bool isNull; if (PointerIsValid(fInfo) && FIgetProcOid(fInfo) != InvalidOid) { int i; Datum *attData = (Datum *) palloc(FIgetnArgs(fInfo) * sizeof(Datum)); for (i = 0; i < FIgetnArgs(fInfo); i++) { attData[i] = heap_getattr(tuple, buffer, attrNums[i], hTupDesc, attNull); } returnVal = (Datum) fmgr_array_args(FIgetProcOid(fInfo), FIgetnArgs(fInfo), (char **) attData, &isNull); pfree(attData); *attNull = FALSE; } else { returnVal = heap_getattr(tuple, buffer, attrNums[attOff], hTupDesc, attNull); } return returnVal; }