Re: anti-join chosen even when slower than old plan - Mailing list pgsql-performance

From Kevin Grittner
Subject Re: anti-join chosen even when slower than old plan
Date
Msg-id 4CD983E002000025000374D7@gw.wicourts.gov
Whole thread Raw
In response to Re: anti-join chosen even when slower than old plan  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
Tom Lane <tgl@sss.pgh.pa.us> wrote:

> However, you'd have to be spending a lot of time chasing through
> long HOT chains before that would happen enough to make this a
> hotspot...

That makes it all the more mysterious, then.  These tables are
insert-only except for a weekly delete of one week of the oldest
data.  The parent table, with the date, is deleted first, then this
table deletes "where not exists" a corresponding parent.  I can't
see how we'd ever have a HOT chain in these tables.

Is there anything in particular you'd like me to check?

-Kevin

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