Re: slow query on tables with new columns added. - Mailing list pgsql-performance

From Filip Rembiałkowski
Subject Re: slow query on tables with new columns added.
Date
Msg-id CAP_rww=w1fHxy01-hMciengN=6ovxtZWN4FgRDNdywb-Htm3iQ@mail.gmail.com
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In response to slow query on tables with new columns added.  ("M. D." <lists@turnkey.bz>)
Responses Re: slow query on tables with new columns added.  ("M. D." <lists@turnkey.bz>)
List pgsql-performance

2011/9/23 M. D. <lists@turnkey.bz>

I did a software upgrade, and with it came a new feature where when selecting a customer it queries for the sum of a few columns.  This takes 7 seconds for the 'Cash Sale' customer - by far the most active customer. I'd like to see if it's possible to get it down a bit by changing settings.


To make things clear before we search for a solution. You wrote "by changing settings". Is it the only option? Can't you change the query in software? Can't you change database schema (add indexes etc)?
 

Query:
explain analyse select sum(item_points),sum(disc_points) from invoice left join gltx on invoice.invoice_id = gltx.gltx_id
where gltx.inactive_on is null and gltx.posted = 'Y' and gltx.customer_id = 'A0ZQ2gsACIsEKLI638ikyg'

Aside from other things, you know that LEFT join here is useless? - planner should collapse it to normal join but I'd check.


Filip

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