From: | Wells Oliver <wells(dot)oliver(at)gmail(dot)com> |
---|---|
To: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com> |
Cc: | pgsql-admin <pgsql-admin(at)postgresql(dot)org> |
Subject: | Re: DELETE query and indexes again |
Date: | 2020-07-23 21:51:17 |
Message-ID: | CAOC+FBX+H_PWi9ZoNeqe2FA1L-QtwVwpWCzqGMizQ9K2TqCACA@mail.gmail.com |
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Thread: | |
Lists: | pgsql-admin |
So, uses the index:
explain analyze delete from statcast.play_statistics as ps
using stats as s
where ps.gid = s.gid
and ps.guid = s.guid;
It does this:
-> Index Scan using play_statistics_pkey on play_statistics ps
(cost=0.69..8.59 rows=1 width=26) (actual time=0.008..0.065 rows=108
loops=21063)
Index Cond: ((gid = s.gid) AND (guid = s.guid))
Does not use the index:
explain analyze delete from statcast.play_statistics where gid in (select
distinct gid from stats);
It does this:
-> Seq Scan on play_statistics (cost=0.00..7781818.16 rows=96600516
width=10) (actual time=201.521..396052.101 rows=96556116 loops=1)
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