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Update comments for create_indexscan_node().

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This commit is contained in:
Tom Lane 1999-07-30 00:44:23 +00:00
parent 12c51d9c6e
commit 161be69544
1 changed files with 9 additions and 6 deletions
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15
src/backend/optimizer/plan/createplan.c
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@ -7,7 +7,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.65 1999/07/29 02:48:05 tgl Exp $ * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.66 1999/07/30 00:44:23 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -296,10 +296,13 @@ create_seqscan_node(Path *best_path, List *tlist, List *scan_clauses)
* Returns a indexscan node for the base relation scanned by 'best_path' * Returns a indexscan node for the base relation scanned by 'best_path'
* with restriction clauses 'scan_clauses' and targetlist 'tlist'. * with restriction clauses 'scan_clauses' and targetlist 'tlist'.
* *
* If an 'or' clause is to be used with this index, the indxqual field * The indexqual of the path contains a sublist of implicitly-ANDed qual
* will contain a list of the 'or' clause arguments, e.g., the * conditions for each scan of the index(es); if there is more than one
* clause(OR a b c) will generate: ((a) (b) (c)). Otherwise, the * scan then the retrieved tuple sets are ORed together. The indexqual
* indxqual will simply contain one conjunctive qualification: ((a)). * and indexid lists must have the same length, ie, the number of scans
* that will occur. Note it is possible for a qual condition sublist
* to be empty --- then no index restrictions will be applied during that
* scan.
*/ */
static IndexScan * static IndexScan *
create_indexscan_node(IndexPath *best_path, create_indexscan_node(IndexPath *best_path,
@ -316,7 +319,7 @@ create_indexscan_node(IndexPath *best_path,
/* there should be exactly one base rel involved... */ /* there should be exactly one base rel involved... */
Assert(length(best_path->path.parent->relids) == 1); Assert(length(best_path->path.parent->relids) == 1);
/* check and see if any indices are lossy */ /* check and see if any of the indices are lossy */
foreach(ixid, best_path->indexid) foreach(ixid, best_path->indexid)
{ {
HeapTuple indexTuple; HeapTuple indexTuple;