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Re: ORDER BY user defined function performance issues - Mailing list pgsql-performance

From Tom Lane
Subject Re: ORDER BY user defined function performance issues
Date
Msg-id 16729.1086976782@sss.pgh.pa.us
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In response to ORDER BY user defined function performance issues  (Nick Trainor <nick.trainor@trainorthornton.co.uk>)
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Nick Trainor <nick.trainor@trainorthornton.co.uk> writes:
> What am I missing here?

The ORDER BY query has to evaluate the function at *every* row of the
table before it can sort.  The other query was only evaluating the
function at twenty rows.

            regards, tom lane

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