Horton

Re: PoC plpgsql - possibility to force custom or generic plan

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Pavel Stehule <pavel.stehule@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Simon Riggs <simon@2ndquadrant.com>, Daniel Gustafsson <daniel@yesql.se>, Andrew Dunstan <andrew.dunstan@2ndquadrant.com>, Andres Freund <andres@anarazel.de>, Petr Jelinek <petr.jelinek@2ndquadrant.com>, David Steele <david@pgmasters.net>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Jim Nasby <Jim.Nasby@bluetreble.com>
Date: 2017-09-19T18:37:36Z
Lists: pgsql-hackers 
On Tue, Sep 19, 2017 at 12:45 PM, Pavel Stehule <pavel.stehule@gmail.com> wrote:
>> You can already set a GUC with function scope.  I'm not getting your
>> point.
>
> yes, it is true. But implementation of #option is limited to PLpgSQL - so
> there is not any too much questions - GUC is global - there is lot of
> points:
>
> * what is correct impact on PREPARE
> * what is correct impact on EXECUTE
> * what should be done if this GUC is changed ..

For better or for worse, as a project we've settled on GUCs as a way
to control behavior.  I think it makes more sense to try to apply that
option to new behaviors we want to control than to invent some new
system.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Add plan_cache_mode setting

  2. Add some noreturn attributes to help static analyzers

  3. document when PREPARE uses generic plans

  4. Redesign the plancache mechanism for more flexibility and efficiency.