without extra efforts, because of "GIN" access method has defaul
operator class. But it's not true for GiST:
SELECT am.amname AS index_method, opc.opcname AS opclass_name
FROM pg_am am, pg_opclass opc
WHERE opc.opcmethod = am.oid AND am.amname = 'gist'
ORDER BY index_method, opclass_name;
ÂgistÂÂÂÂÂÂÂÂ | box_ops
ÂgistÂÂÂÂÂÂÂÂ | circle_ops
ÂgistÂÂÂÂÂÂÂÂ | point_ops
ÂgistÂÂÂÂÂÂÂÂ | poly_ops
ÂgistÂÂÂÂÂÂÂÂ | tsquery_ops
ÂgistÂÂÂÂÂÂÂÂ | tsvector_ops
With hstore I don't need to care about it at all.
But thank you very much to points me about indexes on arrays !
2010/11/12 Pavel Stehule <pavel.stehule@xxxxxxxxx>
2010/11/12 Dmitriy Igrishin <dmitigr@xxxxxxxxx>:
> Hey Peter,there are indexes on arrays - you can use a GiST, Gin indexes.
>
> Unfortunately, there is no indexes on arrays (only on expressions).
regards
Pavel
> With hstore we can easily create GiST index for effective access.
>
> 2010/11/12 Peter Bex <Peter.Bex@xxxxxxxxx>
>>
>> On Fri, Nov 12, 2010 at 10:17:50AM +0300, Dmitriy Igrishin wrote:
>> > Hey Mark,
>> >
>> > Yeah, I can't imagine an entity in a real project even with more than
>> > 100
>> > columns. Its rare case.
>> > But if you entities (rows/tuples) of some class (table) can contains
>> > variable
>> > set of columns (properties) you can look at hstore contrib module.
>>
>> What can also work extremely well is storing the data in an array.
>> If you need to access the array based on more meaningful keys you could
>> store key/index pairs in another table.
>>
>> This approach only works well if you have multiple arrays with the same
>> layout. ÂYou probably also need to build up your query dynamically if
>> you need to access variable numbers of datapoints.
>>
>> Cheers,
>> Peter
>> --
>> http://sjamaan.ath.cx
>> --
>> "The process of preparing programs for a digital computer
>> Âis especially attractive, not only because it can be economically
>> Âand scientifically rewarding, but also because it can be an aesthetic
>> Âexperience much like composing poetry or music."
>> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â-- Donald Knuth
>>
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>
>
>
> --
> // Dmitriy.
>
>
>
--
// Dmitriy.
