Skip site navigation (1) Skip section navigation (2)

Re: graph representation of data structures in optimizer

From: Gregory Stark <stark(at)enterprisedb(dot)com>
To: Adriano Lange <adriano(at)c3sl(dot)ufpr(dot)br>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: graph representation of data structures in optimizer
Date: 2009-02-18 16:19:09
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-hackers
Adriano Lange <adriano(at)c3sl(dot)ufpr(dot)br> writes:

> Hi,
> I'm interested in data representation and debug of optimizer routines. Thus,
> I've changed the debug functions of allpaths.c to make a graphviz-like output
> of RelOptInfo structure.
> Any idea about this?
> Is there some project or improvement like this?

Several people have asked about ways to see what possible plans were
considered and why the were rejected, it was one of the repeat offenders in
the recent Postgres Pet Peeves thread so this is a very interesting area to

However I have to say this graph you've generated is amazingly hard to
decipher :) It took me a while to even figure out what information it was

Worse, it's not useful unless you add a lot more information to it such as
what relations are actually being scanned or joined at each path which is
going to make it a hell of a lot harder to read.

I'm not sure how to do any better but I would be fascinated to see any new
images you generate :)

  Gregory Stark
  Ask me about EnterpriseDB's PostGIS support!

In response to


pgsql-hackers by date

Next:From: Mohsen AlimomeniDate: 2009-02-18 16:20:31
Subject: Multi calendar system for pgsql
Previous:From: Gregory StarkDate: 2009-02-18 16:11:17
Subject: Re: pg_migrator progress

Privacy Policy | About PostgreSQL
Copyright © 1996-2017 The PostgreSQL Global Development Group