Re: File system block size and page size

Sybrand Bakker <postbus_at_sybrandb.demon.nl> wrote in message news:<0mk62u8549n498m1aff080p3ajl6vgogeo_at_4ax.com>...
> 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.

Hello,

My system is HP-UX 11.0 which can go until 1024 bytes. Also, I read in "Oracle 8 Tuning T&T" book and many others, that increasing db_file_multiblock_read_count is somwhat equivalent to increasing db_block_size with advantage that there is no need to recreate the DB. So, I dont understand when you said that there is no comparison between
these two parameters.

Question remains: What happened if my system has 8 KB block size and page size is 4 KB, and I set my db_block_size equal to 16 kB or 32 KB?

Thanks Received on Sat Dec 22 2001 - 20:10:29 CET