Re: Various performance questions

Dror Matalon wrote:

> On Mon, Oct 27, 2003 at 01:04:49AM -0500, Christopher Browne wrote:
>>Most of the time involves:
>>
>> a) Reading each page of the table, and
>> b) Figuring out which records on those pages are still "live."
>
>
> The table has been VACUUM ANALYZED so that there are no "dead" records.
> It's still not clear why select count() would be slower than select with
> a "where" clause.

Do a vacuum verbose full and then everything should be within small range of
each other.

Also in the where clause, does explicitly typecasting helps?

Like 'where channel<5000::int2;'

  HTH

  Shridhar