From: | CG <cgg007(at)yahoo(dot)com> |
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To: | "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org> |
Subject: | Removing oids with pg_repack |
Date: | 2023-11-21 18:41:24 |
Message-ID: | 1375662821.3508272.1700592084461@mail.yahoo.com |
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Lists: | pgsql-general |
I have a very large PostgreSQL 9.5 database that still has very large tables with oids. I'm trying to get rid of the oids with as little downtime as possible so I can prep the database for upgrade past PostgreSQL 11. I had a wild idea to mod pg_repack to write a new table without oids. I think it almost works.
To test out my idea I made a new table wipe_oid_test with oids. I filled it with a few rows of data.
Next I make this modification:
CREATE OR REPLACE FUNCTION repack.get_storage_param(oid) RETURNS TEXT AS$$SELECT string_agg(param, ', ')FROM ( -- table storage parameter SELECT unnest(reloptions) as param FROM pg_class WHERE oid = $1 UNION ALL -- TOAST table storage parameter SELECT ('toast.' || unnest(reloptions)) as param FROM ( SELECT reltoastrelid from pg_class where oid = $1 ) as t, pg_class as c WHERE c.oid = t.reltoastrelid UNION ALL /*-- table oid SELECT 'oids = ' || CASE WHEN relhasoids THEN 'true' ELSE 'false' END FROM pg_class WHERE oid = $1*/
SELECT 'oids = false' --my modification
) as t$$LANGUAGE sql STABLE STRICT;
Then I run pg_repack:
$ pg_repack -d mydata -Upostgres -t wipe_oid_test -eLOG: (query) SET search_path TO pg_catalog, pg_temp, publicLOG: (query) SET search_path TO pg_catalog, pg_temp, publicLOG: (query) select repack.version(), repack.version_sql()LOG: (query) SET statement_timeout = 0LOG: (query) SET search_path = pg_catalog, pg_temp, publicLOG: (query) SET client_min_messages = warningLOG: (query) SELECT t.*, coalesce(v.tablespace, t.tablespace_orig) as tablespace_dest FROM repack.tables t, (VALUES (quote_ident($1::text))) as v (tablespace) WHERE (relid = $2::regclass) ORDER BY t.relname, t.schemanameLOG: (param:0) = (null)LOG: (param:1) = wipe_oid_testINFO: repacking table "public.wipe_oid_test"LOG: (query) SELECT pg_try_advisory_lock($1, CAST(-2147483648 + $2::bigint AS integer))LOG: (param:0) = 16185446LOG: (param:1) = 2273648077LOG: (query) BEGIN ISOLATION LEVEL READ COMMITTEDLOG: (query) SET LOCAL statement_timeout = 100LOG: (query) LOCK TABLE public.wipe_oid_test IN ACCESS EXCLUSIVE MODELOG: (query) RESET statement_timeoutLOG: (query) SELECT pg_get_indexdef(indexrelid) FROM pg_index WHERE indrelid = $1 AND NOT indisvalidLOG: (param:0) = 2273648077LOG: (query) SELECT indexrelid, repack.repack_indexdef(indexrelid, indrelid, $2, FALSE) FROM pg_index WHERE indrelid = $1 AND indisvalidLOG: (param:0) = 2273648077LOG: (param:1) = (null)LOG: (query) SELECT repack.conflicted_triggers($1)LOG: (param:0) = 2273648077LOG: (query) CREATE TYPE repack.pk_2273648077 AS (k text)LOG: (query) CREATE TABLE repack.log_2273648077 (id bigserial PRIMARY KEY, pk repack.pk_2273648077, row public.wipe_oid_test)LOG: (query) CREATE TRIGGER repack_trigger AFTER INSERT OR DELETE OR UPDATE ON public.wipe_oid_test FOR EACH ROW EXECUTE PROCEDURE repack.repack_trigger('INSERT INTO repack.log_2273648077(pk, row) VALUES( CASE WHEN $1 IS NULL THEN NULL ELSE (ROW($1.k)::repack.pk_2273648077) END, $2)')LOG: (query) ALTER TABLE public.wipe_oid_test ENABLE ALWAYS TRIGGER repack_triggerLOG: (query) SELECT repack.disable_autovacuum('repack.log_2273648077')LOG: (query) BEGIN ISOLATION LEVEL READ COMMITTEDLOG: (query) SELECT pg_backend_pid()LOG: (query) SELECT pid FROM pg_locks WHERE locktype = 'relation' AND granted = false AND relation = 2273648077 AND mode = 'AccessExclusiveLock' AND pid <> pg_backend_pid()LOG: (query) COMMITLOG: (query) BEGIN ISOLATION LEVEL SERIALIZABLELOG: (query) SELECT set_config('work_mem', current_setting('maintenance_work_mem'), true)LOG: (query) SELECT coalesce(array_agg(l.virtualtransaction), '{}') FROM pg_locks AS l LEFT JOIN pg_stat_activity AS a ON l.pid = a.pid LEFT JOIN pg_database AS d ON a.datid = d.oid WHERE l.locktype = 'virtualxid' AND l.pid NOT IN (pg_backend_pid(), $1) AND (l.virtualxid, l.virtualtransaction) <> ('1/1', '-1/0') AND (a.application_name IS NULL OR a.application_name <> $2) AND a.query !~* E'^\\s*vacuum\\s+' AND a.query !~ E'^autovacuum: ' AND ((d.datname IS NULL OR d.datname = current_database()) OR l.database = 0)LOG: (param:0) = 15246LOG: (param:1) = pg_repackLOG: (query) DELETE FROM repack.log_2273648077LOG: (query) SELECT pid FROM pg_locks WHERE locktype = 'relation' AND granted = false AND relation = 2273648077 AND mode = 'AccessExclusiveLock' AND pid <> pg_backend_pid()LOG: (query) SET LOCAL statement_timeout = 100LOG: (query) LOCK TABLE public.wipe_oid_test IN ACCESS SHARE MODELOG: (query) RESET statement_timeoutLOG: (query) CREATE TABLE repack.table_2273648077 WITH (oids = false) TABLESPACE pg_default AS SELECT k,v FROM ONLY public.wipe_oid_test WITH NO DATALOG: (query) INSERT INTO repack.table_2273648077 SELECT k,v FROM ONLY public.wipe_oid_testLOG: (query) SELECT repack.disable_autovacuum('repack.table_2273648077')LOG: (query) COMMITLOG: (query) CREATE UNIQUE INDEX index_2273648083 ON repack.table_2273648077 USING btree (k)LOG: (query) SELECT repack.repack_apply($1, $2, $3, $4, $5, $6)LOG: (param:0) = SELECT * FROM repack.log_2273648077 ORDER BY id LIMIT $1LOG: (param:1) = INSERT INTO repack.table_2273648077 VALUES ($1.*)LOG: (param:2) = DELETE FROM repack.table_2273648077 WHERE (k) = ($1.k)LOG: (param:3) = UPDATE repack.table_2273648077 SET (k, v) = ($2.k, $2.v) WHERE (k) = ($1.k)LOG: (param:4) = DELETE FROM repack.log_2273648077 WHERE id IN (LOG: (param:5) = 1000LOG: (query) SELECT pid FROM pg_locks WHERE locktype = 'virtualxid' AND pid <> pg_backend_pid() AND virtualtransaction = ANY($1)LOG: (param:0) = {}LOG: (query) SAVEPOINT repack_sp1LOG: (query) SET LOCAL statement_timeout = 100LOG: (query) LOCK TABLE public.wipe_oid_test IN ACCESS EXCLUSIVE MODELOG: (query) RESET statement_timeoutLOG: (query) SELECT repack.repack_apply($1, $2, $3, $4, $5, $6)LOG: (param:0) = SELECT * FROM repack.log_2273648077 ORDER BY id LIMIT $1LOG: (param:1) = INSERT INTO repack.table_2273648077 VALUES ($1.*)LOG: (param:2) = DELETE FROM repack.table_2273648077 WHERE (k) = ($1.k)LOG: (param:3) = UPDATE repack.table_2273648077 SET (k, v) = ($2.k, $2.v) WHERE (k) = ($1.k)LOG: (param:4) = DELETE FROM repack.log_2273648077 WHERE id IN (LOG: (param:5) = 0LOG: (query) SELECT repack.repack_swap($1)LOG: (param:0) = 2273648077LOG: (query) COMMITLOG: (query) BEGIN ISOLATION LEVEL READ COMMITTEDLOG: (query) SAVEPOINT repack_sp1LOG: (query) SET LOCAL statement_timeout = 100LOG: (query) LOCK TABLE public.wipe_oid_test IN ACCESS EXCLUSIVE MODELOG: (query) RESET statement_timeoutLOG: (query) SELECT repack.repack_drop($1, $2)LOG: (param:0) = 2273648077LOG: (param:1) = 4LOG: (query) COMMITLOG: (query) BEGIN ISOLATION LEVEL READ COMMITTEDLOG: (query) ANALYZE public.wipe_oid_testLOG: (query) COMMITLOG: (query) SELECT pg_advisory_unlock($1, CAST(-2147483648 + $2::bigint AS integer))LOG: (param:0) = 16185446LOG: (param:1) = 2273648077
But PostgreSQL still thinks that the table has oids:
mydata=# \d+ wipe_oid_test Table "public.wipe_oid_test" Column | Type | Modifiers | Storage | Stats target | Description --------+------+-----------+----------+--------------+------------- k | text | not null | extended | | v | text | | extended | | Indexes: "wipe_oid_test_pkey" PRIMARY KEY, btree (k)Has OIDs: yes
mydata=# select oid,* from wipe_oid_test; oid | k | v -----+---+--- 0 | 1 | 2 0 | 3 | 4 0 | a | b 0 | c | d(4 rows)
I can modify pg_class and set relhasoids = false, but it isn't actually eliminating the oid column. `\d+` will report not report that it has oids, but the oid column is still present and returns the same result before updating pg_class.
So I'm definitely missing something. I really need a point in the right direction.... Please help! ;)
CG
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