Re: [HACKERS] [FEATURE PATCH] pg_stat_statements with plans (v02)

From: Julian Markwort <julian(dot)markwort(at)uni-muenster(dot)de>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Andres Freund <andres(at)anarazel(dot)de>, Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>, Simon Riggs <simon(at)2ndquadrant(dot)com>, David Steele <david(at)pgmasters(dot)net>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, marius(dot)timmer(at)uni-muenster(dot)de, arne(dot)scheffer(at)uni-muenster(dot)de
Subject: Re: [HACKERS] [FEATURE PATCH] pg_stat_statements with plans (v02)
Date: 2018-03-08 13:58:34
Message-ID: 1520517514.762.15.camel@uni-muenster.de
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I've goofed up now, sorry for failing to attach my updated patch.

Am Donnerstag, den 08.03.2018, 14:55 +0100 schrieb Julian Markwort:
> Tom Lane wrote on 2018-03-02:
> > You need to make your changes in a 1.5--1.6
> > upgrade file. Otherwise there's no clean path for existing
> > installations
> > to upgrade to the new version.
>
> I've adressed all the issues that were brought up so far:
> 1. there is now only an added 1.5--1.6.sql file.
> 2. the overhead, as previously discussed (as much as a 12% decrease
> in
> TPS during read-only tests), is now gone, the problem was that I was
> collecting the plan String before checking if it needed to be stored
> at
> all.
> The patched version is now 99.95% as fast as unmodified
> pg_stat_statements.
> 3. I've cleaned up my own code and made sure it adheres to GNU C
> coding
> style, I was guilty of some // comments and curly brackets were
> sometimes in the same line as my control structures.
>
> I'd love to hear more feedback, here are two ideas to polish this
> patch:
> a) Right now, good_plan and bad_plan collection can be activated and
> deactivated with separate GUCs. I think it would be sensible to
> collect
> either both or none. (This would result in fewer convoluted
> conditionals.)
> b) Would you like to be able to tune the percentiles yourself, to
> adjust for the point at which a new plan is stored?
>
> Greetings
> Julian

Attachment Content-Type Size
pgss_plans_v03.patch text/x-patch 30.3 KB

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