pg.ddx.io pgsql-admin@postgresql.org mailing list archive help / color / mirror / Atom feed From: Achilleas Mantzios <achill@matrix.gatewaynet.com>
To: pgsql-admin@lists.postgresql.org
Subject: Index ignored on pkid = curval('some_seq'), used with pkid = (select curval(''some_seq') )
Date: Wed, 27 Feb 2019 10:54:11 +0200
Message-ID: <0ee1a3a2-7394-d518-2e22-790a84ef558c@matrix.gatewaynet.com> (raw )
On Postgresql 10 and 11
begin;
insert into itemshist(id,repdate,systemdate,done,username) VALUES(1454349,current_date,current_timestamp,'t','foo');
dynacom=# explain analyze update itemshist set reason='{foo,bar}' where pkid = currval(('public.itemshist_pkid_seq'::text)::regclass);
QUERY PLAN
------------------------------------------------------------------------------------------------------------------------
Update on itemshist (cost=0.00..412082.16 rows=1 width=167) (actual time=15833.238..15833.238 rows=0 loops=1)
-> Seq Scan on itemshist (cost=0.00..412082.16 rows=1 width=167) (actual time=14444.143..15833.210 rows=1 loops=1)
Filter: (pkid = currval(('public.itemshist_pkid_seq'::text)::regclass))
Rows Removed by Filter: 14470046
Planning Time: 0.095 ms
Trigger for constraint $1: time=0.240 calls=1
Trigger itemshist_dbmirror_trig: time=3.101 calls=1
Execution Time: 15836.636 ms
(8 rows)
-- but if I compare against select currval it uses the index:
dynacom=# explain analyze update itemshist set reason='{foo,bar}' where pkid = ( SELECT currval(('public.itemshist_pkid_seq'::text)::regclass));
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------
Update on itemshist (cost=0.45..8.47 rows=1 width=167) (actual time=0.048..0.048 rows=0 loops=1)
InitPlan 1 (returns $0)
-> Result (cost=0.00..0.01 rows=1 width=8) (actual time=0.006..0.006 rows=1 loops=1)
-> Index Scan using itemshist_pkey on itemshist (cost=0.43..8.45 rows=1 width=167) (actual time=0.028..0.033 rows=1 loops=1)
Index Cond: (pkid = $0)
Planning Time: 0.095 ms
Trigger for constraint $1: time=0.145 calls=1
Trigger itemshist_dbmirror_trig: time=3.026 calls=1
Execution Time: 3.273 ms
(9 rows)
--
Achilleas Mantzios
IT DEV Lead
IT DEPT
Dynacom Tankers Mgmt
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Cc: achill@matrix.gatewaynet.com, pgsql-admin@lists.postgresql.org
Subject: Re: Index ignored on pkid = curval('some_seq'), used with pkid = (select curval(''some_seq') )
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