Re: How to set block size during DB creation??

On Fri, 16 Jul 1999 14:13:34 -0500, "Paul Woods" <paulwoods_at_nospaminter-intelli.com> wrote:

>I am using Oracle 8i on NT. My understanding is that DB_BLOCK_SIZE must be
>set at the time of database creation and cannot be altered afterwards. Is
>there a way to set this using the Database Configuration Assistant, or do I
>need to create the database manually?
>
>A related question: What is the optimal DB_BLOCK_SIZE setting for NT? I
>know the default is 2048, but what is optimal? I have heard that 8192 is
>ideal but I'm confused about whether NT can support that. Doesn't NT itself
>use 4096 byte blocks?
>
>Paul
>
>--
>Paul R. Woods
>Webmaster
>Interactive Intelligence, Inc.
>paulwoods_at_inter-intelli.com
>http://www.inter-intelli.com
>
>
>

Just change the db_block size to 8196 (or whatever) in the init.ora.

NT does I/O in 2048 chucks but can block 64K. 8K is a good multiple of both.

Remember to set other parameters that feed off DB_BLOCK_SIZE. ie:

DB_FILE_MULTIBLOCK_READ_COUNT = 64K / db_block_size (ie 8K - 64/8= 8)
DB_BUFFERS = I start with 1/2 * total memory = db_block_buffers *
db_block size. (assuming a single instance)

there are a couple of others that escape me at the moment, but these are the big 2.

8K does speed up most i/o intensive dbs. however, if you do a lot of small record random reads, at some point a larger block size will hurt you. Really know your db if you plan to set it above 8K. Also think on the impact this has on your RBS if you do a lot of updates.

Enjoy..............

Doug Coan
Senior Client Server Integrator
AEGON USA
dcoan_at_aegonusa.com

Doug Coan
Senior Client Server Systems Integrator DCoan_at_aegonusa.com
"Live to Learn and Learn to Live" Received on Sun Jul 18 1999 - 08:37:03 CDT