Re: Oracle Block Sizes
Date: 1995/05/28
Message-ID: <3qbbcp$ibk_at_caesar.ultra.net>#1/1
mikel_at_nic (Michael LeWinter) wrote:
>I know that it's not a one size fits all question, but
>is there a generally accepted block size (2k, 4k, 8k ...) parameter for Oracle
>when the primary use is a query-only system.
>If it makes any difference, it is a HP UX system with Fast and Wide 2GB SCSI
>disks.
>Any feedback would be much appreciated. Thanks in advance.
>--
>This is a test signature
There are a lot of factors to consider but the one I use most frequently is index depth.
Oracle uses B-trees for everything. The more levels in the tree, the more logical I/O's that will be required to access any row. If I have many large indexes (eg. many levels in tree) I tend toward a larger block size.
Note that the minimum table size is 2 blocks if you have a lot of very small tables, large blocks sizes tend to waste space.
Warning: make sure you have enough memory. If you double the blocks size and keep db_blocks the same (as you should) the size of the SGA will nearly double. Received on Sun May 28 1995 - 00:00:00 CEST