Andreas Joseph Krogh <andreas@xxxxxxxxxx> writes: > Hi all. > > Using PG-9.4.0 I'm seeing this trying to delete from an "entity"-master table: > > *# explain analyze delete from onp_crm_entity where entity_id IN (select tmp.delivery_id from temp_delete_delivery_id tmp); > QUERY PLAN > --------------------------------------------------------------------------------------------------------------------------------------------------- > Delete on onp_crm_entity (cost=0.43..5673.40 rows=1770 width=12) (actual time=7.370..7.370 rows=0 loops=1) > -> Nested Loop (cost=0.43..5673.40 rows=1770 width=12) (actual time=0.050..1.374 rows=108 loops=1) > -> Seq Scan on temp_delete_delivery_id tmp (cost=0.00..27.70 rows=1770 width=14) (actual time=0.014..0.080 rows=108 loops=1) > -> Index Scan using onp_crm_entity_pkey on onp_crm_entity (cost=0.43..3.18 rows=1 width=14) (actual time=0.010..0.011 rows=1 loops=108) > Index Cond: (entity_id = tmp.delivery_id) > Planning time: 0.314 ms > Trigger for constraint onp_crm_activity_entity_id_fkey: time=4.141 calls=108 > Trigger for constraint ... > Trigger for constraint ... > Trigger for constraint ... > > > I have lots of tables referencing onp_crm_entity(entity_id) so I expect the poor performance of deleting from it is caused by all the triggers firing to check > FKI-constraints. > > Are there any ways around this or do people simply avoid having FKs in schemas like this? The classic problem is that one/more of your referring tables is non-trivial in size and you are missing an index on the referring column(s). Insure that this condition does not exist before butchering your design :-) > Thanks. > > -- > Andreas Joseph Krogh > CTO / Partner - Visena AS > Mobile: +47 909 56 963 > andreas@xxxxxxxxxx > www.visena.com > [cid] > -- Jerry Sievers Postgres DBA/Development Consulting e: postgres.consulting@xxxxxxxxxxx p: 312.241.7800 -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
