diff options
Diffstat (limited to 'src/backend/optimizer/path/indxpath.c')
| -rw-r--r-- | src/backend/optimizer/path/indxpath.c | 30 |
1 files changed, 15 insertions, 15 deletions
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c index 466c369cde5..2dbbd0bfbef 100644 --- a/src/backend/optimizer/path/indxpath.c +++ b/src/backend/optimizer/path/indxpath.c @@ -9,7 +9,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.191.2.1 2005/11/14 23:54:35 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.191.2.2 2005/11/22 18:23:10 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -262,8 +262,8 @@ find_usable_indexes(PlannerInfo *root, RelOptInfo *rel, * to imply the predicate. If so, we could use the index in the * current context. * - * We set useful_predicate to true iff the predicate was proven using the - * current set of clauses. This is needed to prevent matching a + * We set useful_predicate to true iff the predicate was proven using + * the current set of clauses. This is needed to prevent matching a * predOK index to an arm of an OR, which would be a legal but * pointlessly inefficient plan. (A better plan will be generated by * just scanning the predOK index alone, no OR.) @@ -524,19 +524,19 @@ choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths) * always take the first, and sequentially add on paths that result in a * lower estimated cost. * - * We also make some effort to detect directly redundant input paths, as can - * happen if there are multiple possibly usable indexes. For this we look - * only at plain IndexPath inputs, not at sub-OR clauses. And we consider - * an index redundant if all its index conditions were already used by - * earlier indexes. (We could use predicate_implied_by to have a more - * intelligent, but much more expensive, check --- but in most cases + * We also make some effort to detect directly redundant input paths, as + * can happen if there are multiple possibly usable indexes. For this we + * look only at plain IndexPath inputs, not at sub-OR clauses. And we + * consider an index redundant if all its index conditions were already + * used by earlier indexes. (We could use predicate_implied_by to have a + * more intelligent, but much more expensive, check --- but in most cases * simple pointer equality should suffice, since after all the index * conditions are all coming from the same RestrictInfo lists.) * - * XXX is there any risk of throwing away a useful partial index here because - * we don't explicitly look at indpred? At least in simple cases, the - * partial index will sort before competing non-partial indexes and so it - * makes the right choice, but perhaps we need to work harder. + * XXX is there any risk of throwing away a useful partial index here + * because we don't explicitly look at indpred? At least in simple cases, + * the partial index will sort before competing non-partial indexes and so + * it makes the right choice, but perhaps we need to work harder. * * Note: outputting the selected sub-paths in selectivity order is a good * thing even if we weren't using that as part of the selection method, @@ -920,8 +920,8 @@ check_partial_indexes(PlannerInfo *root, RelOptInfo *rel) * index. For now, the test only uses restriction clauses (those in * baserestrictinfo). --Nels, Dec '92 * - * XXX as of 7.1, equivalence class info *is* available. Consider improving - * this code as foreseen by Nels. + * XXX as of 7.1, equivalence class info *is* available. Consider + * improving this code as foreseen by Nels. */ foreach(ilist, rel->indexlist) |