Comments on: Autoallocate and PX http://jonathanlewis.wordpress.com/2007/05/29/autoallocate-and-px/ Just another Oracle weblog Fri, 24 May 2013 13:27:07 +0000 hourly 1 http://wordpress.com/ By: PX and system allocation « Oracle Scratchpad http://jonathanlewis.wordpress.com/2007/05/29/autoallocate-and-px/#comment-47157 Thu, 14 Jun 2012 17:01:23 +0000 http://jonathanlewis.wordpress.com/2007/05/29/autoallocate-and-px/#comment-47157 [...] few years ago (2007) I wrote about a problem that could appear when you mixed parallel execution with system managed extent allocation. A couple of years later I added a note that Christian Antognini had observed a patch in 11.1.0.7 [...]

]]> By: Amir Riaz http://jonathanlewis.wordpress.com/2007/05/29/autoallocate-and-px/#comment-37612 Sun, 24 Oct 2010 09:01:13 +0000 http://jonathanlewis.wordpress.com/2007/05/29/autoallocate-and-px/#comment-37612 Jonathon,

That ‘s solve our problem. we have a huge data warehouse with 32K block size and with quite a good IO system with oracle 11r2. but we never manage to get db_file_multiblock_read_count=128 and we have alot of holes in tablespace also. Now we are setting initial=8M but not able to decide Next value. Also a value of db_file_multiblock_read_count=256 is under discussion. our system admin says that we can change this value by setting the maxphy tunable parameter of solaris.

]]> By: 碎片(Fragmentation)–介绍 « a db thinker's home http://jonathanlewis.wordpress.com/2007/05/29/autoallocate-and-px/#comment-36865 Tue, 27 Jul 2010 07:21:54 +0000 http://jonathanlewis.wordpress.com/2007/05/29/autoallocate-and-px/#comment-36865 [...] 假如说,每个区间都只能是64K,这会限制我们将发起的“db file multiblock read”请求的大小吗或者这些请求可以跨越区间边界读取吗?如果这个表空间是有两个(或多个)数据文件组成,而这些区间又是以“轮流”在两个文件之间分配的,这会影响读操作的方式吗?如果我们尝试进行并行表扫描,这些限制在“direct path read”上会不会有所不同呢?如果你的运行系统是一个数据仓库,需要花费大量的时间运行这种操作,那么这些就是你需要回答的问题.(例如,参见我3年前写的关于运行并行查询时的部分IO异常的记录,以及Christian Antognini在大约几年后描述的Oracle 11g中的一个相关改进.) [...]

]]> By: Fragmentation 1 « Oracle Scratchpad http://jonathanlewis.wordpress.com/2007/05/29/autoallocate-and-px/#comment-36739 Tue, 13 Jul 2010 20:34:39 +0000 http://jonathanlewis.wordpress.com/2007/05/29/autoallocate-and-px/#comment-36739 [...] type of operation then these are just some of the questions you need to answer. (See, for example, a note I wrote three years ago about some of the anomalies of I/O sizes when running parallel query, and a related enhancement in [...]

]]> By: Ted http://jonathanlewis.wordpress.com/2007/05/29/autoallocate-and-px/#comment-10229 Wed, 30 May 2007 18:20:50 +0000 http://jonathanlewis.wordpress.com/2007/05/29/autoallocate-and-px/#comment-10229 Fantastic,
This clearly explains some of the issues I’ve been seeing and have been experimenting over the last week.
Works done now…. Thanks Jonathan.

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