--- In ib-support@y..., "Nico Callewaert" <ncw@c...> wrote:

> Hi again,
>
> I don't know if I have to disagree with Paul, but as a test I

backuped and

> restored the database and I changed the buffersize from 4096 to

2048
and it

> looks slower to me now ???
>

Sorry for repost, Yahoo users. My post via atkin newsgroup is
unsuccesfull again.
Hi, Nico. My English don't allow me to give full and clear
explanation. But. Size of the page mainly influent on performance by
2 aspects
1. How much index entries can be placed on the page (therefore how
many pages should be visited when building access bitmaps). This
means large page is better.
2. OS and hardware expensies to read larger number of bytes when
need little of page contens. This means small page is better.

Good compromise to start is set page size equal to HDD cluster size
and check statistics on indexes. If index depth>3 then it is
ineffective and experiments should be continued, try increase page
size and check index'es depth and subjective performance. I have read
somewhere that on NTFS page size > 4096 is bad, but can't remember
where and don't tried - I use Linix to run SQL servers.

Sorry if simplified somewhat to point of incorrection but general
direction is certainly right.

Best regards.