In my tests it greatly depends on if index writes are random or sequential. My test time goes down from few hours to seconds if I add to the end of index.
As for me, best comparision would be to make two equal int4 columns with same data as in int8, two indexes, then perform the test. My bet it will be slower than int8.
Четвер, 4 серпня 2011 р. користувач Robert Ayrapetyan <
robert.ayrapetyan@comodo.com> написав:
> All you are saying disproves following:
>
> in experiment I replaces bigint index:
>
> CREATE INDEX ix_t_big ON test.t USING btree (id_big) TABLESPACE tblsp_ix;
>
> with 4 (!) other indexes:
>
>>> If you look at the rest of my mail - you would notice 50 times
>>> difference in performance.
>>> What you would say?
>>
>> That accessing a page from RAM is more than 50 times as fast as a
>> random access of that page from disk.
>>
>> -Kevin
>>
>
>
>
> --
> Ayrapetyan Robert,
> Comodo Anti-Malware Data Processing Analysis and Management System (CAMDPAMS)
>
http://repo-qa.camdpams.odessa.office.comodo.net/mediawiki/index.php >
--
Best regards,
Vitalii Tymchyshyn