Date: Wed, 2 Mar 2011 16:12:36 -0800 (PST)
From: sverhagen <sverhagen@wps-nl.com>
To: pgsql-performance@postgresql.org
Message-ID: <1299111156142-3407330.post@n5.nabble.com>
In-Reply-To: <4D6DBC63.7080109@squeakycode.net>
References: <1299024855300-3405914.post@n5.nabble.com>
	<4D6DBC63.7080109@squeakycode.net>
Subject: Re: Performance trouble finding records through related records
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Thanks for your help already!
Hope you're up for some more :-)


Andy Colson wrote:
> 
> First off, excellent detail.
> 
> Second, your explain analyze was hard to read... but since you are not
> really interested in your posted query, I wont worry about looking at
> it... but... have you seen:
> 
> http://explain.depesz.com/
> 

Thanks for that. Using it below :-)


Andy Colson wrote:
> 
> If you run the individual queries, without the union, are the part's slow
> too?
> 

Only problem is the second part. So that part can safely be isolated. Also
the following does not play a role at this point: WHERE events2.eventtype_id
IN
(100,103,105,...

Then I went ahead and denormalized the transactionId on both ends, so that
both events_events records and events_eventdetails records have the
transactionId (or NULL). That simplifies the query to this:

	SELECT events_events.* FROM events_events WHERE transactionid IN (
		SELECT transactionid FROM events_eventdetails customerDetails
		WHERE customerDetails.keyname='customer_id'
		AND substring(customerDetails.value,0,32)='1957'
		AND transactionid IS NOT NULL
	) ORDER BY id LIMIT 50;

To no avail. Also changing the above WHERE IN into implicit/explicit JOIN's
doesn't make more than a marginal difference. Should joining not be very
efficient somehow?

http://explain.depesz.com/s/Pnb

The above link nicely shows the hotspots, but I am at a loss now as how to
approach them.


Andy Colson wrote:
> 
> Looked like your row counts (the estimate vs the actual) were way off,
> have you analyzed lately?
> 

Note sure what that means.
Isn't all the maintenance nicely automated through my config?


Andy Colson wrote:
> 
> I could not tell from the explain analyze if an index was used, but I
> notice you have a ton of indexes on events_events table.
> 

Yes, a ton of indexes, but still not the right one :-)


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