From 193a85477460fb1c46b60d39a78ac9d849f58c72 Mon Sep 17 00:00:00 2001 From: Jeff Davis Date: Mon, 13 Apr 2026 12:09:40 -0700 Subject: [PATCH v1] catcache.c: always use C_COLLATION_OID. Previously, texthashfast/texteqfast used DEFAULT_COLLATION_OID. As the comments stated, that was arbitrary anyway -- if the collation actually mattered, it should use the column's actual collation. (In the catalog, some text columns are the default collation and some are "C".) When any deterministic collation will do, it's best to consistently use the simplest and fastest one, so this commit chooses C_COLLATION_OID. The original report was to allow the catalog cache to be used in early code paths before CheckMyDatabase(), such as GUC processing in the walsender. Using C_COLLATION_OID solves that problem as well, because it's always available. Reported-by: Andrey Borodin Discussion: https://postgr.es/m/D18AD72A-5004-4EF8-AF80-10732AF677FA@yandex-team.ru --- src/backend/utils/cache/catcache.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index 87ed5506460..a8e7bf649d2 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -205,6 +205,10 @@ nameeqfast(Datum a, Datum b) char *ca = NameStr(*DatumGetName(a)); char *cb = NameStr(*DatumGetName(b)); + /* + * Catalogs only use deterministic collations, so ignore column collation + * and use fast path. + */ return strncmp(ca, cb, NAMEDATALEN) == 0; } @@ -213,6 +217,10 @@ namehashfast(Datum datum) { char *key = NameStr(*DatumGetName(datum)); + /* + * Catalogs only use deterministic collations, so ignore column collation + * and use fast path. + */ return hash_bytes((unsigned char *) key, strlen(key)); } @@ -244,17 +252,20 @@ static bool texteqfast(Datum a, Datum b) { /* - * The use of DEFAULT_COLLATION_OID is fairly arbitrary here. We just - * want to take the fast "deterministic" path in texteq(). + * Catalogs only use deterministic collations, so ignore column collation + * and use "C" locale for efficiency. */ - return DatumGetBool(DirectFunctionCall2Coll(texteq, DEFAULT_COLLATION_OID, a, b)); + return DatumGetBool(DirectFunctionCall2Coll(texteq, C_COLLATION_OID, a, b)); } static uint32 texthashfast(Datum datum) { - /* analogously here as in texteqfast() */ - return DatumGetInt32(DirectFunctionCall1Coll(hashtext, DEFAULT_COLLATION_OID, datum)); + /* + * Catalogs only use deterministic collations, so ignore column collation + * and use "C" locale for efficiency. + */ + return DatumGetInt32(DirectFunctionCall1Coll(hashtext, C_COLLATION_OID, datum)); } static bool -- 2.43.0