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Flushing Cursor SQL Plan Out of Library Cache

I can never remember how to do this.

I wanted to flush a specific SQL execution plan out of the Oracle 11g SQL Library Cache so that I could try and compare a before and after SQL execution scenario using SQL trace and then tkprof’ing it.
Here’s the link to the blog that helped me remember again:

https://prutser.wordpress.com/2009/04/19/flushing-a-cursor-out-of-the-library-cache/

Thanks.

Enable SAP* in Netweaver 7.0

If you’ve lost the Administrator password or you want to log in as SAP* in your pure Java stack environment, this can be a little tricky as the way to set the password for the SAP* user in configtool is not as user friendly as you might think.

Log into configtool by opening an X-Windows session (on UNIX), and then execute: /usr/sap/<SID>/JC<SYS#>/j2ee/configtool/configtool.sh (.bat on Windows).

NOTE: Once you enable the SAP* user, you will not be able to log into the system as any other users e.g. Administrator or J2EE_ADMIN.

In the configtool screen, expand the “Global server configuration -> services” branches:

Click the “com.sap.security.core.ume.service” item:

On the right hand side, scroll down to the ume.superadmin.activated option:

Set the “Value:” field to “TRUE”:

Now single click the “ume.superadmin.password” item:

You can’t see the password and the “Value:” field looks like it doesn’t accept input, but it does.
Type the new password in to the “Value:” field at the bottom (even though the cursor doesn’t move):

Now click “Set” on the right:

You will be prompted to re-enter the password:

Click Save:

You should restart the J2EE stack before trying to log in as SAP*.

SAP on HP-UX

There are various methods of tuning an SAP system, but sometimes the operating system vendor will permit specific tuning so that the SAP system can take better advantage of the available resources.
Usually, you can find whitpapers on the O/S or hardware vendor’s web site, but also SAP will themselves develop a range of SAP notes that will offer avice and guidance when running on certain approved hardware partners.
If you’re using HP-UX 11iv3 (11.31) and you are running SAP, then here are some gems direct from SAP themselves:

Note:
172747 HP-UX OS Parameter Recommendations
798194 HP-UX async IO trace files
837670 HP-UX OS Patch Requirements
918279 HP-UX SAPOSCOL Versions
1077887 HP-UX filesystem options
1329878 Using non-default pagesize on HP-UX
1351051 Support of Oracle on HPVM
1457063 HP-UX Consolidating SAP Systems
1575609 Future HP-UX support for SAP on Oracle

I would highly recommend the OS Parameters note.
If you’re suffering I/O performance issues, make sure that you have set the correct block size as per 1077887.
A huge (>10%) reduction in memory usage can be obtained following 1329878, but only if you are using Oracle 11g.

Using the direct I/O option alone on a VxFS 5.0 environment decreased Data Protector backup times by over 1 quarter e.g. a 1.5 hour backup reduced to ~1 hour.

I haven’t investigated the HPUX_SCHED_NOAGE O/S parameter option yet (I need the audacity to recommend it to the server team!), but according to this excellent blog post by Christian Bilien, it should help your environment significantly if you’re running more than one Oracle database on a SMP system.
My reasoning is that there will be more than one CPU hungry Oracle thread and they could each be battling against each other (ageing each other out) even more so in a well tuned system with less I/O (large SGA/PGA and well tuned SQL) meaning less voluntary context switches and more forced ones. It’s possible that in this situation, without HPUX_SCHED_NOAGE, you could start to see CPU bottlenecks.

HP also produce their own performance recommendations for running Oracle.
Here’s one on the HP recommended filesystem IO options.
Notice that it says if you’re using VxFS v5.0, you don’t need to worry about 1KB block sizes on Redo and Archive Log partitions.

WARNING: Take heed in the warning about Progress databases on file system partitions with directio enabled on the mount options. I have personally experienced issues where Progress applications have had a 20x decrease in performance! It’s a fact, Progress is not very good without the file system cache.

This one is specific to tuning HP-UX TCP/IP. Very useful if you’re seeing networking bandwidth problems in you environment.

Finally, the HP-UX Performance Cookbook provides an excellent source of information.
I have noticed that some of the SAP Oracle recommended parameters (830576 “Parameter Recommendations for Oracle 10g”) are specific to HP-UX, I have found that a good set of descriptions for some of these are covered in this HP Oracle paper: The Oracle Database on HP Integrity servers.

It’s really a trade off between what SAP say and what Oracle say.
Obviously Oracle know there own database system, so anything Oracle says can also be included.
I generally follow the top down rule, where SAP overrides anything that is contradictory from HP or Oracle, Oracle overrides anything contradictory from HP, and I only implement any parameters from HP if neither Oracle or SAP have anything to say on the matter:
– HP (OS)
– Oracle (RDBMS)
– SAP

SAP User Groups

Apart from the roles, profiles and authorisation objects involved in SAP security controls, there is also an additional level. User groups.
The user groups in an SAP system can be used to control access to certain authorisation objects (i.e as a restriction in a profile), or used as a method of tagging different types of users to permit certain types of administrative delegation.
Therefore permitting a super set of users to administer passwords for a smaller sub-set of users of a certain user group.

So how do you create user groups? Use transaction SUGR to define the groups, then assign the users in SU01 or SU10.
Take a look at authorisation object S_USER_GRP.

Monitoring Index Usage In Oracle 10G Using V$OBJECT_USAGE

Have you got some large indexes creeping around?
Some of my systems have 10GB indexes.
These take valuable resources away from the Oracle database:
– DML time (INSERT, UPDATE etc).
– Stats generation time.
– Segment space (hard disk).
– Structure validation time.
– Recovery time.

Removing the index may not be an option. But what if it’s not actually used!!

How can we tell if it’s used?
Well you could monitor all SQL in the shared pool using the AWR capture script https://www.remote-dba.net/oracle_10g_tuning/t_oracle_index_usage_tracking.htm, or you could use Jonathan’s script https://jonathanlewis.wordpress.com/segment-scans/ to see if the index segment(s) has been scanned (full scan). But these don’t comprehensively give you a definitive answer.
There could be holes in your monitoring.

Instead, you could use the V$OBJECT_USAGE view to monitor index usage.
Although a very basic method, if you only want to know definitively if an index has been used or not, then it gives you the answer.
It is described in great detail here: https://wiki.oracle.com/page/Monitor+Index+Usage

Turn on:
alter index <INDEX> monitoring usage;

ALTER INDEX SAPSR3."JCDS~Z01" monitoring usage;

Turn off:
alter index <INDEX> nomonitoring usage;

ALTER INDEX SAPSR3."JCDS~Z01" nomonitoring usage;

Check usage (must be as owner of monitored objects):
select count(1) from v$object_usage;

Or use query below to see all monitored objects:

SELECT u.name owner , io.name index_name , t.name table_name , DECODE(bitand(i.flags, 65536), 0, 'NO', 'YES') monitoring , DECODE(bitand(ou.flags, 1), 0, 'NO', 'YES') used , ou.start_monitoring start_monitoring , ou.end_monitoring END_MONITORING FROM sys.user$ u , sys.obj$ io , sys.obj$ t , sys.ind$ i , sys.object_usage ou WHERE i.obj# = ou.obj# AND io.obj# = ou.obj# AND t.obj# = i.bo# AND u.user# = io.owner#;