Thread: TODO
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
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. +
> 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
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