Re: BUG #8274: Wildly insane boolean selectivity estimates

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: andrew(at)tao11(dot)riddles(dot)org(dot)uk
Cc: pgsql-bugs(at)postgresql(dot)org
Subject: Re: BUG #8274: Wildly insane boolean selectivity estimates
Date: 2013-07-24 04:22:28
Message-ID: 4165.1374639748@sss.pgh.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-bugs

andrew(at)tao11(dot)riddles(dot)org(dot)uk writes:
> The handling of freq_null for estimating IS NOT TRUE/FALSE for boolean
> columns which are all null or almost all null (enough that analyze doesn't
> find any non-null values to put in MCV) is completely off in the weeds.

Doh, definitely a bit of brain fade there :-(

> Suggested fix at:
> https://gist.github.com/RhodiumToad/5901567

Seems reasonable, will fix.

regards, tom lane

In response to

Browse pgsql-bugs by date

  From Date Subject
Next Message hailong.li 2013-07-24 10:54:07 BUG #8327: a bug of spgist index in a heavy write condition
Previous Message digoal 2013-07-24 01:54:34 BUG #8326: pgbench tps wrong BUG