Re: explain plans with information about (modified) gucs - Mailing list pgsql-hackers

From Tomas Vondra
Subject Re: explain plans with information about (modified) gucs
Date
Msg-id c76b7ec7-70db-6ec9-cc1a-73ffb53f6b2e@2ndquadrant.com
Whole thread Raw
In response to Re: explain plans with information about (modified) gucs  (Alvaro Herrera <alvherre@2ndquadrant.com>)
Responses Re: explain plans with information about (modified) gucs  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers

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


pgsql-hackers by date:

Previous
From: Andres Freund
Date:
Subject: Re: Reducing header interdependencies around heapam.h et al.
Next
From: Amit Langote
Date:
Subject: Re: Query with high planning time at version 11.1 compared versions10.5 and 11.0