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Database parameter

Former Member
0 Kudos

Hi all,

We have done the following database parameter changes

SQL> show parameter _securefiles_concurrency_estimate

NAME TYPE VALUE

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

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

_securefiles_concurrency_estimate integer 50

SQL> show parameter _simple_view_merging

NAME TYPE VALUE

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

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

_simple_view_merging boolean FALSE

We have also applied latest SBP after that changes  Entire performance has

been downgraded.

Please suggest.

Regards,

MS

Accepted Solutions (0)

Answers (2)

Answers (2)

former_member182034
Active Contributor
0 Kudos

hi MS,

Please have a look at this SAP Note.

Note 1431798 - Oracle 11.2.0: Database Parameter Settings

Regards,

hasanajsh
Active Contributor
0 Kudos

Hi,

What is the Oracle release and version?

Former Member
0 Kudos

Oracle version 11.2.0.3  ( 11g)

ACE-SAP
Active Contributor
0 Kudos

Hello

Parameter _securefiles_concurrency_estimate should improve performance for update access on securefiles (aka Lob)

Securefiles DMLs cause high 'buffer busy waits' & 'enq: TX - contention' wait events leading to whole database performance degradation [ID 1532311.1]

=> As a workaround (until the change gets built in to 11.2.0.4 and 12c) you need to set _securefiles_concurrency_estimate = 50 before creating the tables.

1887235  - Increased buffer busy waits/contention on Oracle securefiles

To avoid performance problems caused by concurrency on securefiles increase the value of parameter to 50.

This will be the default value of _securefiles_concurrency_estimate for Oracle releases >11.2.0.3.

The parameter _simple_view_merging, can have quite disturbing impacts, make sure you are in the appropriate patch version before setting that parameter to false.

Check the information provided by Stefan in that message : http://scn.sap.com/thread/3452822

Best regards

hasanajsh
Active Contributor
0 Kudos

In 1431798  - Oracle 11.2.0: Database Parameter Settings

you can find 2 more notes specifically referring to these parameters:

Note 1887235

Note 1915485