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| author | Peter Geoghegan <pg@bowt.ie> | 2024-11-20 13:37:08 -0500 |
|---|---|---|
| committer | Peter Geoghegan <pg@bowt.ie> | 2024-11-20 13:37:08 -0500 |
| commit | 70743376987af2393e42f3cfc2def4a472070659 (patch) | |
| tree | 16473d5e4571787dadde0302d8c17b9fcaa24a30 /src | |
| parent | 94131cd53c1552efe85c3e8120356c22cd658163 (diff) | |
| download | postgresql-70743376987af2393e42f3cfc2def4a472070659.tar.gz postgresql-70743376987af2393e42f3cfc2def4a472070659.zip | |
Refine nbtree = redundancy preprocessing comment.
Spell out how a = key associated with a SAOP array renders a > key
against the same index column redundant at the relevant point inside
_bt_preprocess_keys.
Follow-up to commit 5bf748b8.
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/access/nbtree/nbtutils.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/src/backend/access/nbtree/nbtutils.c b/src/backend/access/nbtree/nbtutils.c index d7603250279..896696ff724 100644 --- a/src/backend/access/nbtree/nbtutils.c +++ b/src/backend/access/nbtree/nbtutils.c @@ -2668,8 +2668,14 @@ _bt_preprocess_keys(IndexScanDesc scan) /* * If = has been specified, all other keys can be eliminated as - * redundant. If we have a case like key = 1 AND key > 2, we can - * set qual_ok to false and abandon further processing. + * redundant. Note that this is no less true if the = key is + * SEARCHARRAY; the only real difference is that the inequality + * key _becomes_ redundant by making _bt_compare_scankey_args + * eliminate the subset of elements that won't need to be matched. + * + * If we have a case like "key = 1 AND key > 2", we set qual_ok to + * false and abandon further processing. We'll do the same thing + * given a case like "key IN (0, 1) AND key > 2". * * We also have to deal with the case of "key IS NULL", which is * unsatisfiable in combination with any other index condition. By |