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authorTomas Vondra2024-08-19 11:31:51 +0000
committerTomas Vondra2024-08-19 11:31:51 +0000
commit5cb902e9d5a99a0e1a2c9098555447e097102e39 (patch)
treed612284f04572454efa8abf805f983335aaf3e78
parent4fdb6558c2709c799643d26f3f956395ae72a8ef (diff)
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
-rw-r--r--src/backend/commands/dbcommands.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c
index 7a7e2c6e3ef..d00ae40e192 100644
--- a/src/backend/commands/dbcommands.c
+++ b/src/backend/commands/dbcommands.c
@@ -1790,7 +1790,9 @@ 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,