v19-0001-Update-header-comment-for-lookup_type_cache.patch
application/octet-stream
Filename: v19-0001-Update-header-comment-for-lookup_type_cache.patch
Type: application/octet-stream
Part: 0
Message:
Re: type cache cleanup improvements
Patch
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API reference →
Format: format-patch
Series: patch v19-0001
Subject: Update header comment for lookup_type_cache()
| File | + | − |
|---|---|---|
| src/backend/utils/cache/typcache.c | 9 | 0 |
From 5f9c300e039854949cbd1337200b227018426c05 Mon Sep 17 00:00:00 2001 From: Alexander Korotkov <akorotkov@postgresql.org> Date: Tue, 22 Oct 2024 10:30:40 +0300 Subject: [PATCH v19 1/2] Update header comment for lookup_type_cache() Describe the way we handle concurrent invalidation messages. Discussion: https://postgr.es/m/CAPpHfdsQhwUrnB3of862j9RgHoJM--eRbifvBMvtQxpC57dxCA%40mail.gmail.com Reviewed-by: Andrei Lepikhov, Artur Zakirov, Pavel Borisov --- src/backend/utils/cache/typcache.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/src/backend/utils/cache/typcache.c b/src/backend/utils/cache/typcache.c index 2ec136b7d30..f142624ad2e 100644 --- a/src/backend/utils/cache/typcache.c +++ b/src/backend/utils/cache/typcache.c @@ -351,6 +351,15 @@ type_cache_syshash(const void *key, Size keysize) * invalid. Note however that we may fail to find one or more of the * values requested by 'flags'; the caller needs to check whether the fields * are InvalidOid or not. + * + * Note that while filling TypeCacheEntry we might process concurrent + * invalidation messages, causing our not-yet-filled TypeCacheEntry to be + * invalidated. In this case, we typically only clear flags while values are + * still available for the caller. It's expected that the caller holds + * enough locks on type-depending objects that the values are still relevant. + * It's also important that the tupdesc is filled after all other + * TypeCacheEntry items for TYPTYPE_COMPOSITE. So, tupdesc can't get + * invalidated during the lookup_type_cache() call. */ TypeCacheEntry * lookup_type_cache(Oid type_id, int flags) -- 2.39.5 (Apple Git-154)