diff options
Diffstat (limited to 'src/backend/access/index/genam.c')
| -rw-r--r-- | src/backend/access/index/genam.c | 74 |
1 files changed, 40 insertions, 34 deletions
diff --git a/src/backend/access/index/genam.c b/src/backend/access/index/genam.c index c1971133ce1..5eb0d78facc 100644 --- a/src/backend/access/index/genam.c +++ b/src/backend/access/index/genam.c @@ -7,7 +7,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/access/index/genam.c,v 1.21 1999/07/17 20:16:40 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/access/index/genam.c,v 1.22 1999/12/30 05:04:50 tgl Exp $ * * NOTES * many of the old access method routines have been turned into @@ -39,7 +39,7 @@ * All other states cannot occur. * * Note: - *It would be possible to cache the status of the previous and + * It would be possible to cache the status of the previous and * next item pointer using the flags. * ---------------------------------------------------------------- */ @@ -55,9 +55,19 @@ * We don't know how the various AMs do locking, however, so we don't * do anything about that here. * - * The intent is that an AM implementor will define a front-end routine - * that calls this one, to fill in the scan, and then does whatever kind - * of locking he wants. + * The intent is that an AM implementor will define a beginscan routine + * that calls RelationGetIndexScan, to fill in the scan, and then does + * whatever kind of locking he wants. + * + * At the end of a scan, the AM's endscan routine undoes the locking, + * but does *not* call IndexScanEnd --- the higher-level index_endscan + * routine does that. (We can't do it in the AM because index_endscan + * still needs to touch the IndexScanDesc after calling the AM.) + * + * Because of this, the AM does not have a choice whether to call + * RelationGetIndexScan or not; its beginscan routine must return an + * object made by RelationGetIndexScan. This is kinda ugly but not + * worth cleaning up now. * ---------------------------------------------------------------- */ @@ -72,16 +82,11 @@ * relation -- index relation for scan. * scanFromEnd -- if true, begin scan at one of the index's * endpoints. - * numberOfKeys -- count of scan keys (more than one won't - * necessarily do anything useful, yet). + * numberOfKeys -- count of scan keys. * key -- the ScanKey for the starting position of the scan. * * Returns: * An initialized IndexScanDesc. - * - * Side Effects: - * Bumps the ref count on the relation to keep it in the cache. - * * ---------------- */ IndexScanDesc @@ -118,6 +123,30 @@ RelationGetIndexScan(Relation relation, return scan; } +/* ---------------- + * IndexScanEnd -- End an index scan. + * + * This routine just releases the storage acquired by + * RelationGetIndexScan(). Any AM-level resources are + * assumed to already have been released by the AM's + * endscan routine. + * + * Returns: + * None. + * ---------------- + */ +void +IndexScanEnd(IndexScanDesc scan) +{ + if (!IndexScanIsValid(scan)) + elog(ERROR, "IndexScanEnd: invalid scan"); + + if (scan->keyData != NULL) + pfree(scan->keyData); + + pfree(scan); +} + #ifdef NOT_USED /* ---------------- * IndexScanRestart -- Restart an index scan. @@ -160,29 +189,6 @@ IndexScanRestart(IndexScanDesc scan, } /* ---------------- - * IndexScanEnd -- End and index scan. - * - * This routine is not used by any existing access method, but is - * suitable for use if you don't want to do sophisticated locking. - * - * Returns: - * None. - * - * Side Effects: - * None. - * ---------------- - */ -void -IndexScanEnd(IndexScanDesc scan) -{ - if (!IndexScanIsValid(scan)) - elog(ERROR, "IndexScanEnd: invalid scan"); - - pfree(scan); -} - - -/* ---------------- * IndexScanMarkPosition -- Mark current position in a scan. * * This routine isn't used by any existing access method, but is the |