TODO

Started by Tatsuo Ishiiover 13 years ago4 messages
#1Tatsuo Ishii
ishii@postgresql.org

I found this in https://wiki.postgresql.org/wiki/Todo :

Improve ability to display optimizer analysis using OPTIMIZER_DEBUG

What does this actually mean?

Add GUC switch to enable optimizer debug on/off?
More fancy/useful info should be printed?
If so, what kind of information is required?
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp

#2Bruce Momjian
bruce@momjian.us
In reply to: Tatsuo Ishii (#1)
Re: TODO

On Tue, Aug 21, 2012 at 12:16:11PM +0900, Tatsuo Ishii wrote:

I found this in https://wiki.postgresql.org/wiki/Todo :

Improve ability to display optimizer analysis using OPTIMIZER_DEBUG

What does this actually mean?

Add GUC switch to enable optimizer debug on/off?
More fancy/useful info should be printed?
If so, what kind of information is required?

Well, right now, OPTIMIZER_DEBUG lets you see what plans were considered
and removed. I was thinking that information should be available
without a special compiled binary.

--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +

#3Josh Berkus
josh@agliodbs.com
In reply to: Bruce Momjian (#2)
Re: TODO

Well, right now, OPTIMIZER_DEBUG lets you see what plans were considered
and removed. I was thinking that information should be available
without a special compiled binary.

+1. It would also be popular with our academic users.

--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com

#4Peter Geoghegan
peter@2ndquadrant.com
In reply to: Bruce Momjian (#2)
Re: TODO

On 23 August 2012 20:21, Bruce Momjian <bruce@momjian.us> wrote:

On Tue, Aug 21, 2012 at 12:16:11PM +0900, Tatsuo Ishii wrote:

I found this in https://wiki.postgresql.org/wiki/Todo :

Improve ability to display optimizer analysis using OPTIMIZER_DEBUG

What does this actually mean?

Add GUC switch to enable optimizer debug on/off?
More fancy/useful info should be printed?
If so, what kind of information is required?

Well, right now, OPTIMIZER_DEBUG lets you see what plans were considered
and removed. I was thinking that information should be available
without a special compiled binary.

That seems like an unreasonable burden on what OPTIMIZER_DEBUG can do.
If you can't build Postgres from source, something that is relatively
low barrier, you have little hope of sensibly interpreting low-level
output from the planner. However, I could get behind having it as a
configure option, which it is currently not. It would probably also
make sense to expose SELECTIVITY_DEBUG and GEQO_DEBUG.

--
Peter Geoghegan http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training and Services