From: Richard Huxton <dev@archonet.com>
To: Tobias Brox <tobias@nordicbet.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: "nice"/low priority Query
Date: Wed, 03 Aug 2005 09:53:29 +0100
Message-ID: <42F08609.5060709@archonet.com> (raw)
In-Reply-To: <20050802195915.GA9691@tobias.lan>
References: <20050802160434.GD9278@tobias.lan>
<20050802195915.GA9691@tobias.lan>
Tobias Brox wrote:
> [Tobias Brox - Tue at 06:04:34PM +0200]
>
>>(...) and at one
>>point in the code I'm even asking the database for "explain plan", grepping
>>out the estimated cost number, and referring the user to take contact with
>>the IT-dept if he really needs the report. But I digress.
>
>
> I just came to think about some more "dirty" tricks I can do. I have turned
> on stats collection in the configuration; now, if I do:
>
> select count(*) from pg_stat_activity where not current_query like '<IDLE>%';
>
> or, eventually:
>
> select count(*) from pg_stat_activity
> where not current_query like '<IDLE>%' and query_start+'1 second'<now();
>
> it will give a hint about how busy the database server is, thus I can
> eventually let the application sleep and retry if there are any other heavy
> queries in progress.
Or - create a table with an estimated_cost column, when you start a new
"heavy" query, insert that query's cost, then sleep
SUM(estimated_cost)/100 secs or something. When the query ends, delete
the cost-row.
Hmm - actually rather than dividing by 100, perhaps make it a tunable value.
--
Richard Huxton
Archonet Ltd
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: dev@archonet.com, tobias@nordicbet.com
Subject: Re: "nice"/low priority Query
In-Reply-To: <42F08609.5060709@archonet.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox