Re: Multicolumn index including tsvector.

On 24 Nov 2009, at 24:08, Kris Gale wrote:

>      Table "public.example"
>  Column  |   Type   | Modifiers
> ---------+----------+-----------
>  body    | text     |
>  vectors | tsvector |
>  user_id | bigint   |
>
> I've got btree_gin and btree_gist installed, so I can make a composite index on vectors and user_id (which is a
bigint).


A bigint for userid? How many billions of users do you expect to get?

A bigint is 8 bytes or 64 bits. I think a normal int (32-bits) would be quite sufficient; it allows up to 2 billion
users.It uses less storage space for both the data and the indices too. 

And as Tom already said casting can be a problem with bigints, not only if certain operators aren't defined for
comparisonbetween int and bigint, but you'll also see a performance hit if table data you compare to needs to be
upcastedto a bigint; joins come to mind. 

Alban Hertroys

--
If you can't see the forest for the trees,
cut the trees and you'll see there is no forest.


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