Re: Help optimizing a slow index scan

On Fri, 17 Mar 2006, Evgeny Gridasov wrote:

> Try contrib/btree_gist.

contrib/btree_gist does nothing more than  built-in btree - it's just
an support for multicolumn GiST indices.

> I've tried that one, but for my case it didn't help much.
> The performance was almost equal or even slower than built-in btree.
>
> On Fri, 17 Mar 2006 08:53:44 -0700
> Dan Harris <fbsd@drivefaster.net> wrote:
>
>> Dan Harris wrote:
>>> Markus Bertheau wrote:
>>>> Have you tried using a GIST index on lat & long? These things are
>>>> meant for two-dimensional data, whereas btree doesn't handle
>>>> two-dimensional data that well. How many rows satisfy either of the
>>>> long / lat condition?
>>>>
>>>>
>>>>>
>>> According to the analyze, less than 500 rows matched.  I'll look into
>>> GIST indexes, thanks for the feedback.
>>>
>>> -Dan
>>>
>>> ---------------------------(end of broadcast)---------------------------
>>> TIP 2: Don't 'kill -9' the postmaster
>>
>> When I try to create a GIST index, I get the following error:
>>
>> create index eventgeo_lat_idx on eventgeo using GIST (lat);
>>
>> ERROR:  data type double precision has no default operator class for
>> access method "gist"
>> HINT:  You must specify an operator class for the index or define a
>> default operator class for the data type.
>>
>> I'm not sure what a "default operator class" is, exactly..
>>
>> -Dan
>>
>> ---------------------------(end of broadcast)---------------------------
>> TIP 5: don't forget to increase your free space map settings
>>
>
>
>

     Regards,
         Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
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