1 /*-------------------------------------------------------------------------
4 * general index access method routines
6 * Copyright (c) 1994, Regents of the University of California
10 * $Header: /cvsroot/pgsql/src/backend/access/index/indexam.c,v 1.11 1997/08/12 22:51:48 momjian Exp $
13 * index_open - open an index relation by relationId
14 * index_openr - open a index relation by name
15 * index_close - close a index relation
16 * index_beginscan - start a scan of an index
17 * index_rescan - restart a scan of an index
18 * index_endscan - end a scan
19 * index_insert - insert an index tuple into a relation
20 * index_delete - delete an item from an index relation
21 * index_markpos - mark a scan position
22 * index_restrpos - restore a scan position
23 * index_getnext - get the next tuple from a scan
24 * ** index_fetch - retrieve tuple with tid
25 * ** index_replace - replace a tuple
26 * ** index_getattr - get an attribute from an index tuple
27 * index_getprocid - get a support procedure id from the rel tuple
29 * IndexScanIsValid - check index scan
32 * This file contains the index_ routines which used
33 * to be a scattered collection of stuff in access/genam.
35 * The ** routines: index_fetch, index_replace, and index_getattr
36 * have not yet been implemented. They may not be needed.
39 * Scans are implemented as follows:
41 * `0' represents an invalid item pointer.
42 * `-' represents an unknown item pointer.
43 * `X' represents a known item pointers.
44 * `+' represents known or invalid item pointers.
45 * `*' represents any item pointers.
47 * State is represented by a triple of these symbols in the order of
48 * previous, current, next. Note that the case of reverse scans works
52 * (1) + + - + 0 0 (if the next item pointer is invalid)
53 * (2) + X - (otherwise)
54 * (3) * 0 0 * 0 0 (no change)
55 * (4) + X 0 X 0 0 (shift)
56 * (5) * + X + X - (shift, add unknown)
58 * All other states cannot occur.
60 * Note: It would be possible to cache the status of the previous and
61 * next item pointer using the flags.
63 *-------------------------------------------------------------------------
68 #include <access/genam.h>
69 #include <utils/relcache.h>
71 #include <storage/lmgr.h>
72 #include <access/heaptuple.h>
75 * undefine macros we aren't going to use that would otherwise
76 * get in our way.. delete is defined in c.h and the am's are
90 /* ----------------------------------------------------------------
91 * macros used in index_ routines
92 * ----------------------------------------------------------------
94 #define RELATION_CHECKS \
95 Assert(RelationIsValid(relation)); \
96 Assert(PointerIsValid(relation->rd_am))
99 Assert(IndexScanIsValid(scan)); \
100 Assert(RelationIsValid(scan->relation)); \
101 Assert(PointerIsValid(scan->relation->rd_am))
103 #define GET_REL_PROCEDURE(x,y) \
104 procedure = relation->rd_am->y; \
105 if (! RegProcedureIsValid(procedure)) \
106 elog(WARN, "index_%s: invalid %s regproc", \
107 CppAsString(x), CppAsString(y))
109 #define GET_SCAN_PROCEDURE(x,y) \
110 procedure = scan->relation->rd_am->y; \
111 if (! RegProcedureIsValid(procedure)) \
112 elog(WARN, "index_%s: invalid %s regproc", \
113 CppAsString(x), CppAsString(y))
116 /* ----------------------------------------------------------------
117 * index_ interface functions
118 * ----------------------------------------------------------------
121 * index_open - open an index relation by relationId
123 * presently the relcache routines do all the work we need
124 * to open/close index relations.
128 index_open(Oid relationId)
130 return RelationIdGetRelation(relationId);
134 * index_openr - open a index relation by name
136 * presently the relcache routines do all the work we need
137 * to open/close index relations.
141 index_openr(char *relationName)
143 return RelationNameGetRelation(relationName);
147 * index_close - close a index relation
149 * presently the relcache routines do all the work we need
150 * to open/close index relations.
154 index_close(Relation relation)
156 RelationClose(relation);
160 * index_insert - insert an index tuple into a relation
164 index_insert(Relation relation,
167 ItemPointer heap_t_ctid,
170 RegProcedure procedure;
171 InsertIndexResult specificResult;
174 GET_REL_PROCEDURE(insert,aminsert);
177 * have the am's insert proc do all the work.
180 specificResult = (InsertIndexResult)
181 fmgr(procedure, relation, datum, nulls, heap_t_ctid, heapRel, NULL);
184 * the insert proc is supposed to return a "specific result" and
185 * this routine has to return a "general result" so after we get
186 * something back from the insert proc, we allocate a
187 * "general result" and copy some crap between the two.
189 * As far as I'm concerned all this result shit is needlessly c
190 * omplicated and should be eliminated. -cim 1/19/91
192 * mao concurs. regardless of how we feel here, however, it is
193 * important to free memory we don't intend to return to anyone.
196 * this "general result" crap is now gone. -ay 3/6/95
200 return (specificResult);
204 * index_delete - delete an item from an index relation
208 index_delete(Relation relation, ItemPointer indexItem)
210 RegProcedure procedure;
213 GET_REL_PROCEDURE(delete,amdelete);
215 fmgr(procedure, relation, indexItem);
219 * index_beginscan - start a scan of an index
223 index_beginscan(Relation relation,
228 IndexScanDesc scandesc;
229 RegProcedure procedure;
232 GET_REL_PROCEDURE(beginscan,ambeginscan);
234 RelationSetRIntentLock(relation);
236 scandesc = (IndexScanDesc)
237 fmgr(procedure, relation, scanFromEnd, numberOfKeys, key);
243 * index_rescan - restart a scan of an index
247 index_rescan(IndexScanDesc scan, bool scanFromEnd, ScanKey key)
249 RegProcedure procedure;
252 GET_SCAN_PROCEDURE(rescan,amrescan);
254 fmgr(procedure, scan, scanFromEnd, key);
258 * index_endscan - end a scan
262 index_endscan(IndexScanDesc scan)
264 RegProcedure procedure;
267 GET_SCAN_PROCEDURE(endscan,amendscan);
269 fmgr(procedure, scan);
271 RelationUnsetRIntentLock(scan->relation);
275 * index_markpos - mark a scan position
279 index_markpos(IndexScanDesc scan)
281 RegProcedure procedure;
284 GET_SCAN_PROCEDURE(markpos,ammarkpos);
286 fmgr(procedure, scan);
290 * index_restrpos - restore a scan position
294 index_restrpos(IndexScanDesc scan)
296 RegProcedure procedure;
299 GET_SCAN_PROCEDURE(restrpos,amrestrpos);
301 fmgr(procedure, scan);
305 * index_getnext - get the next tuple from a scan
307 * A RetrieveIndexResult is a index tuple/heap tuple pair
311 index_getnext(IndexScanDesc scan,
312 ScanDirection direction)
314 RegProcedure procedure;
315 RetrieveIndexResult result;
318 GET_SCAN_PROCEDURE(getnext,amgettuple);
321 * have the am's gettuple proc do all the work.
324 result = (RetrieveIndexResult)
325 fmgr(procedure, scan, direction);
333 * Some indexed access methods may require support routines that are
334 * not in the operator class/operator model imposed by pg_am. These
335 * access methods may store the OIDs of registered procedures they
336 * need in pg_amproc. These registered procedure OIDs are ordered in
337 * a way that makes sense to the access method, and used only by the
338 * access method. The general index code doesn't know anything about
339 * the routines involved; it just builds an ordered list of them for
340 * each attribute on which an index is defined.
342 * This routine returns the requested procedure OID for a particular
347 index_getprocid(Relation irel,
354 natts = irel->rd_rel->relnatts;
356 loc = irel->rd_support;
360 return (loc[(natts * (procnum - 1)) + (attnum - 1)]);
364 GetIndexValue(HeapTuple tuple,
367 AttrNumber attrNums[],
368 FuncIndexInfo *fInfo,
375 if (PointerIsValid(fInfo) && FIgetProcOid(fInfo) != InvalidOid) {
377 Datum *attData = (Datum *)palloc(FIgetnArgs(fInfo)*sizeof(Datum));
379 for (i = 0; i < FIgetnArgs(fInfo); i++) {
380 attData[i] = (Datum) heap_getattr(tuple,
386 returnVal = (Datum)fmgr_array_args(FIgetProcOid(fInfo),
393 returnVal = (Datum) heap_getattr(tuple, buffer, attrNums[attOff],