diff options
Diffstat (limited to 'src/backend/optimizer/path/pathkeys.c')
| -rw-r--r-- | src/backend/optimizer/path/pathkeys.c | 68 |
1 files changed, 1 insertions, 67 deletions
diff --git a/src/backend/optimizer/path/pathkeys.c b/src/backend/optimizer/path/pathkeys.c index 3e4bcffe2e8..09ad68ecd93 100644 --- a/src/backend/optimizer/path/pathkeys.c +++ b/src/backend/optimizer/path/pathkeys.c @@ -11,7 +11,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.71 2005/07/28 22:27:00 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.72 2005/08/27 22:13:43 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -801,54 +801,6 @@ compare_pathkeys(List *keys1, List *keys2) } /* - * compare_noncanonical_pathkeys - * Compare two pathkeys to see if they are equivalent, and if not whether - * one is "better" than the other. This is used when we must compare - * non-canonicalized pathkeys. - * - * A pathkey can be considered better than another if it is a superset: - * it contains all the keys of the other plus more. For example, either - * ((A) (B)) or ((A B)) is better than ((A)). - * - * Currently, the only user of this routine is grouping_planner(), - * and it will only pass single-element sublists (from - * make_pathkeys_for_sortclauses). Therefore we don't have to do the - * full two-way-subset-inclusion test on each pair of sublists that is - * implied by the above statement. Instead we just verify they are - * singleton lists and then do an equal(). This could be improved if - * necessary. - */ -PathKeysComparison -compare_noncanonical_pathkeys(List *keys1, List *keys2) -{ - ListCell *key1, - *key2; - - forboth(key1, keys1, key2, keys2) - { - List *subkey1 = (List *) lfirst(key1); - List *subkey2 = (List *) lfirst(key2); - - Assert(list_length(subkey1) == 1); - Assert(list_length(subkey2) == 1); - if (!equal(subkey1, subkey2)) - return PATHKEYS_DIFFERENT; /* no need to keep looking */ - } - - /* - * If we reached the end of only one list, the other is longer and - * therefore not a subset. (We assume the additional sublist(s) of - * the other list are not NIL --- no pathkey list should ever have a - * NIL sublist.) - */ - if (key1 == NULL && key2 == NULL) - return PATHKEYS_EQUAL; - if (key1 != NULL) - return PATHKEYS_BETTER1; /* key1 is longer */ - return PATHKEYS_BETTER2; /* key2 is longer */ -} - -/* * pathkeys_contained_in * Common special case of compare_pathkeys: we just want to know * if keys2 are at least as well sorted as keys1. @@ -868,24 +820,6 @@ pathkeys_contained_in(List *keys1, List *keys2) } /* - * noncanonical_pathkeys_contained_in - * The same, when we don't have canonical pathkeys. - */ -bool -noncanonical_pathkeys_contained_in(List *keys1, List *keys2) -{ - switch (compare_noncanonical_pathkeys(keys1, keys2)) - { - case PATHKEYS_EQUAL: - case PATHKEYS_BETTER2: - return true; - default: - break; - } - return false; -} - -/* * get_cheapest_path_for_pathkeys * Find the cheapest path (according to the specified criterion) that * satisfies the given pathkeys. Return NULL if no such path. |