Re: default_statistics_target WAS: max_wal_senders must die

From: Nathan Boley <npboley(at)gmail(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Greg Stark <gsstark(at)mit(dot)edu>, Josh Berkus <josh(at)agliodbs(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: default_statistics_target WAS: max_wal_senders must die
Date: 2010-10-21 02:10:39
Message-ID: AANLkTinsGBjF=wh-N0XuujWB_es8VmAqgGMq=OwfxM7Y@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

> That one's used, too, but the other is used as an upper bound.
> n_distinct tends to come out too small on large tables, so that
> formula is prone to overestimation.  Actually, both formulas are prone
> to overestimation.
>

Right - thanks.

> When this happens depends on the values of a whole boat-load of GUCs...

Well, then doesn't the 'proper' number of buckets depend on a whole
boat-load of GUCs...

-Nathan

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Joshua D. Drake 2010-10-21 02:32:21 Re: default_statistics_target WAS: max_wal_senders must die
Previous Message Tom Lane 2010-10-21 02:07:43 Re: lazy snapshots?