From e498d22e21358e196c1db9b5f1300eae667ea2bd Mon Sep 17 00:00:00 2001 From: Tomas Vondra Date: Mon, 19 Aug 2024 13:31:51 +0200 Subject: [PATCH] Explain dropdb can't use syscache because of TOAST Add a comment explaining dropdb() can't rely on syscache. The issue with flattened rows was fixed by commit 0f92b230f88b, but better to have a clear explanation why the systable scan is necessary. The other places doing in-place updates on pg_database have the same comment. Suggestion and patch by Yugo Nagata. Backpatch to 12, same as the fix. Author: Yugo Nagata Backpatch-through: 12 Discussion: https://postgr.es/m/CAJTYsWWNkCt+-UnMhg=BiCD3Mh8c2JdHLofPxsW3m2dkDFw8RA@mail.gmail.com --- src/backend/commands/dbcommands.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c index af1bb7a728a..11e3b3ec171 100644 --- a/src/backend/commands/dbcommands.c +++ b/src/backend/commands/dbcommands.c @@ -1663,7 +1663,9 @@ dropdb(const char *dbname, bool missing_ok, bool force) pgstat_drop_database(db_id); /* - * Update the database's pg_database tuple + * Get the pg_database tuple to scribble on. Note that this does not + * directly rely on the syscache to avoid issues with flattened toast + * values for the in-place update. */ ScanKeyInit(&scankey, Anum_pg_database_datname,