| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Brendon Gleeson <brendon(at)gleesonprop(dot)co(dot)za> |
| Cc: | pgsql-novice(at)postgresql(dot)org |
| Subject: | Re: query help |
| Date: | 2006-08-10 13:31:24 |
| Message-ID: | 14293.1155216684@sss.pgh.pa.us |
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| Lists: | pgsql-novice |
Brendon Gleeson <brendon(at)gleesonprop(dot)co(dot)za> writes:
> ** apparently count(1) is faster than count(*) and count(id), my Rails log
> confirms this, however I have a limited amount of records at the moment so
> benchmarks are properly inaccurate..
count(1) and count(*) are exactly the same thing (in existing PG
releases anyway), so whatever you're looking at is measurement noise.
count(id) would properly be slower because of the need to examine the
field to see if it's null.
regards, tom lane
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