From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Sergei Agalakov <sergei.agalakov@gmail.com>
Cc: pgsql-hackers@postgresql.org
Subject: Re: explain plans with information about (modified) gucs
Date: Tue, 15 Jan 2019 02:39:49 +0100
Message-ID: <c76b7ec7-70db-6ec9-cc1a-73ffb53f6b2e@2ndquadrant.com> (raw)
In-Reply-To: <201901142213.gt7vdg65pp4d@alvherre.pgsql>
References: <201901142213.gt7vdg65pp4d@alvherre.pgsql>
On 1/14/19 11:13 PM, Alvaro Herrera wrote:
> On 2019-Jan-14, Tomas Vondra wrote:
>
>> The one slightly annoying issue is that currently all the options are
>> formatted as text, including e.g. cpu_tuple_cost. That's because the GUC
>> options may have show hook, so I can't access the value directly (not
>> sure if there's an option around it).
>
> I think the problem is that you'd have to know how to print the value,
> which can be in one of several different C types. You'd have to grow
> some more infrastructure in the GUC tables, I think, and that doesn't
> seem worth the trouble. Printing as text seems enough.
>
I don't think the number of formats is such a big issue - the range of
formats is quite limited: PGC_BOOL, PGC_INT, PGC_REAL, PGC_STRING and
PGC_ENUM. But the show hook simply returns string, and I'm not sure it's
guaranteed it matches the raw value (afaik the assign/show hooks can do
all kinds of funny stuff).
regards
--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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To: pgsql-hackers@postgresql.org
Cc: tomas.vondra@2ndquadrant.com, alvherre@2ndquadrant.com, sergei.agalakov@gmail.com
Subject: Re: explain plans with information about (modified) gucs
In-Reply-To: <c76b7ec7-70db-6ec9-cc1a-73ffb53f6b2e@2ndquadrant.com>
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