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Re: Performance of IN (...) vs. = ANY array[...]

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Benjamin Minshall <minshall(at)intellicon(dot)biz>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Performance of IN (...) vs. = ANY array[...]
Date: 2006-09-15 20:19:21
Message-ID: 5373.1158351561@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-performance
Benjamin Minshall <minshall(at)intellicon(dot)biz> writes:
> What are the advantages or disadvantages of using arrays in this 
> situation?  The = ANY array method makes plpgsql development cleaner, 
> but seems to really lack performance in certain cases.

In existing releases, the form with IN (list-of-scalar-constants)
can be optimized into indexscan(s), but = ANY (array) isn't.

8.2 will treat them equivalently (in fact, it converts IN (...) to
= ANY (ARRAY[...]) !).  So depending on your time horizon, you might
wish to stick with whichever is cleaner for your calling code.

			regards, tom lane

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