Re: An oldie on Blocksize and Performance?

From: Jerry Gitomer <jgitomer_at_hbsrx.com>
Date: Wed, 12 May 1999 11:27:58 -0400
Message-ID: <7hc6gh$puk$1@autumn.news.rcn.net>

Hi Ross,

    If the number of concurrent operations in a block exceeds the value you set in INITRANS Oracle will attempt to allocate additional space in the free space. The problem is the space allocation operation impacts your performance. If the number of concurrent operations in the block is already at MAXTRANS the session will have to wait until a current operation is completed before it can start.

    I can only repeat Kevin Loney's words on the subject:

        "If multiple transactions will simultaneously access the same data block, then the INITRANS parameter should be set to the number of transactions that will concurrently access a single data block."

                Oracle DBA Handbook, Oracle Press  page 121.  (Oracle 7

version)

regards

Jerry Gitomer

---

Ross Mohan wrote in message <7haqhj$hoc_at_sjx-ixn10.ix.netcom.com>...
>Jerry,
>
>thanks....it's at the default: 1 for tables, 2 for indexes, maxes out at
>255....the freelists ( considering
>INSERTs, here ) are set at 8 which is likely a bit low...I thought the ITL
>space in the block header ( as
>opposed to the header block! ) was 'roughly' dynamic and could accomodate
>some growth.....can you
>shed any light on this?
>
>thx
>
>Ross
>
>Jerry Gitomer wrote in message <7h9bom$p65$1_at_autumn.news.rcn.net>...
>>Hi Ross,
>>
>> Have you looked at INITRANS on both the tables and indexes yet? Too
>low
>>a value will have your SQL lined up waiting for access.
>>
>>regards
>>
>>Jerry Gitomer
>
>
>
Received on Wed May 12 1999 - 10:27:58 CDT