Re: Parsing output of EXPLAIN command in PostgreSQL

On 11/10/2011 11:10 AM, Αναστάσιος Αρβανίτης wrote:
> I'm developing an application that requires parsing of
> execution plans (those produced as output by issuing an EXPLAIN [query]
> command). Are you aware of any Java library that I could use for this
> purpose? I found https://github.com/depesz/Pg--Explain but it is built in Perl.
>    

There's also a little Javascript program that consumes the JSON version at:

http://www.postgresonline.com/journal/archives/171-pgexplain90formats_part1.html
http://www.postgresonline.com/journal/archives/174-pgexplain90formats_part2.html

> Also another option I am considering is to use EXPLAIN [query] FORMAT XML which is available in PostgreSQL 9.1.
However,in that case it
 
> would better to have the XML Schema of the generated plans available.
>    

That's the easiest way to solve this problem in Java, and in that case 
most of the text-based code in Pg--Explain will just be a distraction.  
I know some of the earlier versions of XML EXPLAIN included a "DTD" 
option to output that, but I don't see that in the committed code.  I'm 
not sure where that is at actually; it's a good question.

The only reference to doing this I found was Andrew's blog:  
http://people.planetpostgresql.org/andrew/index.php?/archives/32-A-couple-of-nice-tools.html 
where he talks about there being a RELAXNG specification for the XML 
output.  I can't find where that came from either.  Andrew?

-- 
Greg Smith   2ndQuadrant US    greg@2ndQuadrant.com   Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support  www.2ndQuadrant.us