Horton

Re: Track the amount of time waiting due to cost_delay

Nathan Bossart <nathandbossart@gmail.com>

View thread
From: Nathan Bossart <nathandbossart@gmail.com>
To: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Cc: Dilip Kumar <dilipbalaut@gmail.com>, Masahiro Ikeda <ikedamsh@oss.nttdata.com>, "Imseih (AWS), Sami" <simseih@amazon.com>, Masahiko Sawada <sawada.mshk@gmail.com>, pgsql-hackers@lists.postgresql.org, Robert Haas <robertmhaas@gmail.com>
Date: 2024-12-10T17:55:41Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Add delay time to VACUUM/ANALYZE (VERBOSE) and autovacuum logs.

  2. Add cost-based vacuum delay time to progress views.

  3. Add is_analyze parameter to vacuum_delay_point().

  4. Refresh cost-based delay params more frequently in autovacuum

On Mon, Dec 09, 2024 at 04:41:03PM +0000, Bertrand Drouvot wrote:
> +       <structfield>time_delayed</structfield> <type>bigint</type>

I think it's also worth considering names like total_delay and
cumulative_delay.

> +       Total amount of time spent in milliseconds waiting during <xref linkend="guc-vacuum-cost-delay"/>
> +       or <xref linkend="guc-autovacuum-vacuum-cost-delay"/>. In case of parallel
> +       vacuum the reported time is across all the workers and the leader. The
> +       workers update the column no more frequently than once per second, so it
> +       could show slightly old values.

I wonder if it makes sense to provide this value as an interval instead of
the number of milliseconds to make it more human-readable.  I might also
suggest some changes to the description:

	Total accumulated time spent sleeping due to the cost-based vacuum
	delay settings (e.g., vacuum_cost_delay, vacuum_cost_limit).  This
	includes the time that any associated parallel workers have slept, too.
	However, parallel workers report their sleep time no more frequently
	than once per second, so the reported value may be slightly stale.

-- 
nathan