From 12d3345c0d2842a36d0ee2bce06cfe7d3cac84da Mon Sep 17 00:00:00 2001 From: Jeff Davis <jdavis@postgresql.org> Date: Tue, 3 Sep 2024 16:05:58 -0700 Subject: [PATCH] Remember last collation to speed up collation cache. This optimization is to avoid a performance regression in an upcoming patch that will remove lc_collate_is_c(). Discussion: https://postgr.es/m/96a559be83329bc66074a3925ebcfa8ceb16dfc5.camel@j-davis.com Discussion: https://postgr.es/m/646f662e145ab38cff1c04d475f4448f53fc5042.camel@j-davis.com Discussion: https://postgr.es/m/54565933-d82f-4d7c-8f47-288b1b570fd8@eisentraut.org --- src/backend/utils/adt/pg_locale.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c index 643cca05d3..d82e816230 100644 --- a/src/backend/utils/adt/pg_locale.c +++ b/src/backend/utils/adt/pg_locale.c @@ -151,6 +151,13 @@ typedef struct static MemoryContext CollationCacheContext = NULL; static collation_cache_hash *CollationCache = NULL; +/* + * The collation cache is often accessed repeatedly for the same collation, so + * remember the last one used. + */ +static Oid last_collation_cache_oid = InvalidOid; +static pg_locale_t last_collation_cache_locale = NULL; + #if defined(WIN32) && defined(LC_MESSAGES) static char *IsoLocaleName(const char *); #endif @@ -1570,6 +1577,9 @@ pg_newlocale_from_collation(Oid collid) if (collid == DEFAULT_COLLATION_OID) return &default_locale; + if (last_collation_cache_oid == collid) + return last_collation_cache_locale; + cache_entry = lookup_collation_cache(collid); if (cache_entry->locale == 0) @@ -1695,6 +1705,9 @@ pg_newlocale_from_collation(Oid collid) cache_entry->locale = resultp; } + last_collation_cache_oid = collid; + last_collation_cache_locale = cache_entry->locale; + return cache_entry->locale; }