From: Russell Smith <mr-russ@pws.com.au>
To: Michael Glaesemann <grzm@seespotcode.net>
Cc: Stephen Davies <scldad@sdc.com.au>
Cc: pgsql-performance@postgresql.org
Subject: Re: Optimising "in" queries
Date: Thu, 23 Aug 2007 17:34:01 +1000
Message-ID: <46CD3869.90600@pws.com.au> (raw)
In-Reply-To: <AAF53AEE-B98C-45BD-B80F-8FA528BFB98B@seespotcode.net>
References: <200708221210.36770.scldad@sdc.com.au>
<46CC16F3.7060606@pws.com.au>
<AAF53AEE-B98C-45BD-B80F-8FA528BFB98B@seespotcode.net>
Michael Glaesemann wrote:
>
> On Aug 22, 2007, at 5:58 , Russell Smith wrote:
>
>> Stephen Davies wrote:
>>> select count(rdate),rdate from reading where sensor_id in
>>> (1137,1138,1139,1140) group by rdate order by rdate desc limit 1;
>>>
>>>
>> It would have been helpful to see the table definition here. I can
>> say up front that array processing in postgres is SLOW.
>
> Um, what array processing are you seeing here? IN (a, b, b) is not an
> array construct.
Filter: (sensor_id = ANY ('{1137,1138,1139,1140}'::integer[]))
I've never seen this plan item except for when array's are involved. I
could be wrong. I'd like to know how this is generated when you don't
have an array.
Regards
Russell Smith
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To: pgsql-performance@postgresql.org
Cc: mr-russ@pws.com.au, grzm@seespotcode.net, scldad@sdc.com.au
Subject: Re: Optimising "in" queries
In-Reply-To: <46CD3869.90600@pws.com.au>
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