Re: Performance trouble finding records through related records

Andy Colson <andy@xxxxxxxxxxxxxxx> · Thu, 03 Mar 2011 08:55:45 -0600

On 3/3/2011 3:19 AM, sverhagen wrote:

Andy Colson wrote:

For your query, I think a join would be the best bet, can we see its
explain analyze?

Here is a few variations:

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;

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

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

-- http://explain.depesz.com/s/rDh

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

-- http://explain.depesz.com/s/6aB

Thanks for your efforts!

Huh.  Pretty much exactly the same.  I'm sorry but I think I'm at my 
limit.  I'm not sure why the nested loop takes so long, or how to get it 
to use something different.

-Andy

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