Wednesday, June 4, 2008

Re: [GENERAL] full vacuum really slows down query

Yes. 
This is what I do.
1. Vacuum full
2. Reindex force
This is done ever night

My users complained about a report being slow.

I grabbed a dump and restored it to my development machine.

The query worked just fine, but not on the production server.

I did a vacuum full and then reran the query.  Now it performs just as slow as on the production machine.  That is the only change I made.

I am in the process of trying to figure out the EXPLAIN ANALYZE for both queries, but I have never had to read this output and I am unfamiliar with how to find the problem.  I will post both here and maybe someone can help me out.



Joshua D. Drake wrote:
 On Wed, 2008-06-04 at 17:02 -0500, Jason Long wrote:   
I have a query that takes 2 sec if I run it from a freshly restored dump.  If I run a full vacuum on the database it then takes 30 seconds.     
 If you run it a second time after the vacuum full?  Joshua D. Drake     

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