On 2016/01/06 23:50, Tom Lane wrote: > Amit Langote <langote_amit...@lab.ntt.co.jp> writes: >> On 2016/01/06 17:32, Amit Langote wrote: >>> I stumbled upon a possibly strange behavior which may be related to recent >>> initdb changes. For a freshly initdb'd cluster, the following looks fishy: >>> ... >>> These seem to be leftovers of activities of initdb.c's setup_description() >>> and setup_collaction(). > >> I noticed these leftovers are not present in template1. > > Ah, right: they get deleted from template1 correctly when the > initdb-driven session shuts down. But because of the merger into a single > session, they're still there at the instant that we clone template1 into > template0 and postgres databases, and there is nothing to remove them from > there. > > The minimum-change way to deal with it would be to explicitly DROP those > tables when we're done with them. > > A possibly slightly less fragile answer is to run two sessions, the > second of which *only* processes the DB copying steps. > > Neither of these answers seems all that clean to me...
Thanks for fixing this in initdb. So in general, we have no way to get rid of the copies in a new database of temp tables in template1 when the new database is created in the same session as the one connected to template1. For example: template1=# CREATE TEMP TABLE foo(a int); CREATE TABLE template1=# INSERT INTO foo VALUES (1); INSERT 0 1 template1=# CREATE DATABASE test; CREATE DATABASE template1=# \c test You are now connected to database "test" as user "amit". test=# SELECT relname, relnamespace::regnamespace FROM pg_class WHERE relnamespace != 'pg_catalog'::regnamespace AND relnamespace != 'pg_toast'::regnamespace AND relnamespace != 'information_schema'::regnamespace; relname | relnamespace ---------+-------------- foo | pg_temp_2 -- of course, there is no way to open it here (different backend id) test=# SELECT * FROM foo; ERROR: relation "foo" does not exist LINE 1: SELECT * FROM foo; -- nor does it prevent from creating a new temp table foo. test=# CREATE TEMP TABLE foo(a int); CREATE TABLE test=# SELECT relname, relnamespace::regnamespace FROM pg_class WHERE relnamespace != 'pg_catalog'::regnamespace AND relnamespace != 'pg_toast'::regnamespace AND relnamespace != 'information_schema'::regnamespace; relname | relnamespace ---------+-------------- foo | pg_temp_2 foo | pg_temp_3 (2 rows) Maybe, we need not worry too much about this. Thanks, Amit -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
