Re: File system block size and page size

[Quoted] On 21 Dec 2001 02:41:14 -0800, marcco.lucky_at_laposte.net (Marcco) wrote:

>Frank van Bortel <fbortel_at_home.nl> wrote in message news:<3C222FDF.D2E36EA6_at_home.nl>...
>> Marcco wrote:
>> >
>> > Hello,
>> >
>> > I can see that my HP-UX ufs file system is configured
>> > to uses block size of 8k and page size of 4k.
>> > My db_block_size is set equal to 4k (equal to page size).
>> >
>> > How I can resize this. What relation, between db_block_size and
>> > page size. I want to increase this to 8k. Is this is possible?
>> >
>> > Thanks.
>>
>> Probably not without rebuilding the db; upto and including 8.1.7
>> (aka 8i Rel3) block sizes were fixed, and set during db creation.
>> As of 9 you can have different blocksizes for different tablespaces.
>> Hint: always mention versions...
>
>Thank you.
>
>Im using Oracle 8i (8.1.6).
>I have also some questions about: the relation between
>system block size, system page size and oracle db_block_size.
>Is increasing db_file_multiblock_read_count can replace
>db_block_size incresing knowing that my system block size
>is 8k and page size is 4k?
>
>Thanks

No. Increasing db_block_size decreases the overhead in a table. It also allows for bigger records, so for less chained records. db_file_multiblock_read_count is the number of blocks Oracle will read ahead during a full table scan. So, IMO, you are comparing apples and pears.
On most operating systems (with the exception of Solaris) db_block_size * db_file_multiblock_read_count should not exceed 64k, as that is the number of bytes the O/S can read in one request.

Hth

Sybrand Bakker, Senior Oracle DBA

To reply remove -verwijderdit from my e-mail address Received on Fri Dec 21 2001 - 16:21:22 CET