Re: Mini improvement: statement_cost_limit

From: Josh Berkus <josh(at)agliodbs(dot)com>
To: pgsql-hackers(at)postgresql(dot)org
Cc: Gregory Stark <stark(at)enterprisedb(dot)com>, "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "Andrew Dunstan" <andrew(at)dunslane(dot)net>, Hans-Jürgen Schönig <postgres(at)cybertec(dot)at>
Subject: Re: Mini improvement: statement_cost_limit
Date: 2008-08-04 20:53:59
Message-ID: 200808041354.01115.josh@agliodbs.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Greg,

> For such an application this would be a major foot-gun which would give
> a false sense of security simultaneously causing random outages and not
> providing even the protection you're counting on.

Hmmm. That sounds like a call for some testing. While our cost estimation
has some issues, I don't think it's unreliable as all that. And it's easy
enough to document the limitations. If it's 80% accurate, then it's
fixing more problems than it causes. If it's 30% accurate, then obviously
it's a bad idea.

Personally, I don't see much use for this interactively, because an
experienced DBA can easily enough run an EXPLAIN before running the query.
I usually do, on production systems.

--
--Josh

Josh Berkus
PostgreSQL
San Francisco

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Simon Riggs 2008-08-04 21:08:36 Automatic Client Failover
Previous Message Simon Riggs 2008-08-04 20:49:43 Re: Mini improvement: statement_cost_limit