ITPub博客

首页 > Linux操作系统 > Linux操作系统 > Tips--Relevant Parallel Excution INIT.ora Parameters(metalink)

Tips--Relevant Parallel Excution INIT.ora Parameters(metalink)

原创 Linux操作系统 作者:vongates 时间:2019-05-05 17:51:04 0 删除 编辑
Relevant Parallel Excution INIT.ora Parameters From Metalin
http://metalink.oracle.com/metalink/plsql/showdoc?db=Not&id=201799.1
Doc ID: Note:201799.1
Subject: Relevant Parallel Excution INIT.ora Parameters
Type: REFERENCE
Status: PUBLISHED
Content Type: TEXT/PLAIN
Creation Date: 02-JUL-2002
Last Revision Date: 01-MAY-2004
PURPOSE 

--------

To provide a list of parameters that are relevant to parallel

query, Parallel DML and other operation which can be parallized.

We also suggest values for some init.ora parameters to have a good

starting point.

SCOPE & APPLICATION

-------------------

This note is intended for DBAs who are considering using PX

Initialization parameters

-------------------------

The following parameters are currently affecting the behavior

of Parallel Execution in Oracle:

Parameters important for setup

-------------------------------

PARALLEL_ADAPTIVE_MULTI_USER [NOTE:68594.1]

PARALLEL_AUTOMATIC_TUNING (Deprecate in 10G) [NOTE:68595.1]

PARALLEL_BROADCAST_ENABLED (Obsolete in 9.2) [NOTE:68596.1]

PARALLEL_EXECUTION_MESSAGE_SIZE [NOTE:68598.1]

PARALLEL_MAX_SERVERS [NOTE:30790.1]

PARALLEL_MIN_PERCENT [NOTE:39034.1]

PARALLEL_MIN_SERVERS [NOTE:30791.1]

PARALLEL_THREADS_PER_CPU [NOTE:68604.1]

OPTIMIZER_PERCENT_PARALLEL (Obsolete in 9i) [NOTE:39027.1]

Parallel Execution and the use of Memory

----------------------------------------

LARGE_POOL_SIZE [NOTE:47334.1]

SHARED_POOL_SIZE [NOTE:30810.1]

See also

[NOTE:238680.1] Parallel Execution the Large/Shared Pool and ORA-4031

for more background information.

In a Parallel Server or RAC environment, the behavior of parallel

query and PDML is affected by the following parameters also:

------------------------------------------------------------------

PARALLEL_INSTANCE_GROUP [NOTE:47351.1]

INSTANCE_GROUPS [NOTE:47331.1]

Parallelism and Recovery

-------------------------

FAST_START_PARALLEL_ROLLBACK [NOTE:68932.1]

RECOVERY_PARALLELISM [NOTE:30795.1]

Recommeneded Values for PX init.ora Parameter

---------------------------------------------

We would suggest the following for a good starting point with PX.

Maybe some parameter have to be tuned after a while.

Versions prior to 10G.

set parallel_automatic_tuning=true

unset parallel_max_servers

unset parallel_min_servers

unset parallel_execution_message_size*

maybe set parallel_adaptive_multi_user=false**

Version 10G and later

unset parallel_max_servers

unset parallel_min_servers

set parallel_execution_message_size=4096 if adequate memory

maybe set parallel_adaptive_multi_user=false**

* Machines with enough memory can afford to have higher values

here like 8k and 16k but the performance "knee" is at 8k, so higher values

don't give as much benefit.

**This parameter defaults to false unless parallel_automatic_tuning = true.

In 10G it defaults to true.

Users may want to set it to false if they wish to perform first come

first served resource allocation and/or have a queuing mechanism which

submits jobs to the db.

REFERENCES

-----------

Oracle8i Migration Release 3 (8.1.7) Part Number A86632-01

Oracle9i Database Migration Release 2 (9.2) Part No. A96530-02

来自 “ ITPUB博客 ” ,链接:http://blog.itpub.net/29987/viewspace-51856/,如需转载,请注明出处,否则将追究法律责任。

请登录后发表评论 登录
全部评论

注册时间:2018-09-11

  • 博文量
    201
  • 访问量
    145757