This enables changing permanent (logged) tables to unlogged and
vice-versa.
(Docs for ALTER TABLE / SET TABLESPACE got shuffled in an order that
hopefully makes more sense than the original.)
Author: Fabrízio de Royes Mello
Reviewed by: Christoph Berg, Andres Freund, Thom Brown
Some tweaking by Álvaro Herrera
ALTER TABLE old_system_table DROP CONSTRAINT new_system_table_pkey;
ALTER TABLE old_system_table DROP COLUMN othercol;
DROP TABLE old_system_table;
-- set logged
CREATE UNLOGGED TABLE unlogged1(f1 SERIAL PRIMARY KEY, f2 TEXT);
-- check relpersistence of an unlogged table
SELECT relname, relkind, relpersistence FROM pg_class WHERE relname ~ '^unlogged1'
UNION ALL
SELECT 'toast table', t.relkind, t.relpersistence FROM pg_class r JOIN pg_class t ON t.oid = r.reltoastrelid WHERE r.relname ~ '^unlogged1'
UNION ALL
SELECT 'toast index', ri.relkind, ri.relpersistence FROM pg_class r join pg_class t ON t.oid = r.reltoastrelid JOIN pg_index i ON i.indrelid = t.oid JOIN pg_class ri ON ri.oid = i.indexrelid WHERE r.relname ~ '^unlogged1'
-- check relpersistence of an unlogged table after changing to permament
SELECT relname, relkind, relpersistence FROM pg_class WHERE relname ~ '^unlogged1'
UNION ALL
SELECT 'toast table', t.relkind, t.relpersistence FROM pg_class r JOIN pg_class t ON t.oid = r.reltoastrelid WHERE r.relname ~ '^unlogged1'
UNION ALL
SELECT 'toast index', ri.relkind, ri.relpersistence FROM pg_class r join pg_class t ON t.oid = r.reltoastrelid JOIN pg_index i ON i.indrelid = t.oid JOIN pg_class ri ON ri.oid = i.indexrelid WHERE r.relname ~ '^unlogged1'
ORDER BY relname;
relname | relkind | relpersistence
------------------+---------+----------------
toast index | i | p
toast table | t | p
unlogged1 | r | p
unlogged1_f1_seq | S | p
unlogged1_pkey | i | p
(5 rows)
ALTER TABLE unlogged1 SET LOGGED; -- silently do nothing
DROP TABLE unlogged3;
DROP TABLE unlogged2;
DROP TABLE unlogged1;
-- set unlogged
CREATE TABLE logged1(f1 SERIAL PRIMARY KEY, f2 TEXT);
-- check relpersistence of a permanent table
SELECT relname, relkind, relpersistence FROM pg_class WHERE relname ~ '^logged1'
UNION ALL
SELECT 'toast table', t.relkind, t.relpersistence FROM pg_class r JOIN pg_class t ON t.oid = r.reltoastrelid WHERE r.relname ~ '^logged1'
UNION ALL
SELECT 'toast index', ri.relkind, ri.relpersistence FROM pg_class r join pg_class t ON t.oid = r.reltoastrelid JOIN pg_index i ON i.indrelid = t.oid JOIN pg_class ri ON ri.oid = i.indexrelid WHERE r.relname ~ '^logged1'
ALTER TABLE logged1 SET UNLOGGED; -- fails because a foreign key from a permanent table exists
ERROR: cannot change status of table logged1 to unlogged
DETAIL: Logged table logged2 is referenced by table logged1.
ALTER TABLE logged3 SET UNLOGGED; -- skip self-referencing foreign key
ALTER TABLE logged2 SET UNLOGGED;
ALTER TABLE logged1 SET UNLOGGED;
-- check relpersistence of a permanent table after changing to unlogged
SELECT relname, relkind, relpersistence FROM pg_class WHERE relname ~ '^logged1'
UNION ALL
SELECT 'toast table', t.relkind, t.relpersistence FROM pg_class r JOIN pg_class t ON t.oid = r.reltoastrelid WHERE r.relname ~ '^logged1'
UNION ALL
SELECT 'toast index', ri.relkind, ri.relpersistence FROM pg_class r join pg_class t ON t.oid = r.reltoastrelid JOIN pg_index i ON i.indrelid = t.oid JOIN pg_class ri ON ri.oid = i.indexrelid WHERE r.relname ~ '^logged1'
ORDER BY relname;
relname | relkind | relpersistence
----------------+---------+----------------
logged1 | r | u
logged1_f1_seq | S | p
logged1_pkey | i | u
toast index | i | u
toast table | t | u
(5 rows)
ALTER TABLE logged1 SET UNLOGGED; -- silently do nothing
Alvaro Herrera
11 years ago