From: Tom Lane <tgl@sss.pgh.pa.us>
To: Josh Berkus <josh@agliodbs.com>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Cc: Jeff Davis <pgsql@j-davis.com>
Subject: Re: Index usage for tstzrange?
Date: Wed, 20 Mar 2013 23:58:50 -0400
Message-ID: <1326.1363838330@sss.pgh.pa.us> (raw)
In-Reply-To: <514A5088.6060101@agliodbs.com>
References: <514A5088.6060101@agliodbs.com>
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Josh Berkus <josh@agliodbs.com> writes:
> I just noticed that if I use a tstzrange for convenience, a standard
> btree index on a timestamp won't get used for it. Example:
> table a (
> id int,
> val text,
> ts timestamptz
> );
> index a_ts on a(ts);
> SELECT * FROM a WHERE ts <@ tstzrange('2013-01-01','2013-01-01 00:10:00')
> ... will NOT use the index a_ts.
Well, no. <@ is not a btree-indexable operator.
What I find more disturbing is that this is what I get from the example
in HEAD:
regression=# explain SELECT * FROM a WHERE ts <@ tstzrange('2013-01-01','2013-01-01 00:10:00');
ERROR: XX000: type 1184 is not a range type
LOCATION: range_get_typcache, rangetypes.c:1451
Haven't traced through it to determine exactly what's happening, but
isn't this a legitimate usage? And if it isn't, surely a more
user-facing error ought to be getting thrown somewhere upstream of here.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, josh@agliodbs.com, pgsql@j-davis.com
Subject: Re: Index usage for tstzrange?
In-Reply-To: <1326.1363838330@sss.pgh.pa.us>
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