Tuning indexes on RAC environments-4

Excessive undo block shipment and contention for undo buffers I have seen this scenario in one my projects where  Oracle EBS workload is high. When a select statement needs to read a block with active transactions, it has to cleanout the block and undo the changes to create a CR version. If the active transactions […]

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Tuning indexes on RAC environments-3

Reversing the index key This is accomplished by executing the following SQL statement: ALTER INDEX <index_name> REBUILD REVERSE; A reverse key index will invert the bytes of the index key column, so that values originally stored in the same block may be spread across multiple index leaf blocks. That will reduce buffer busy contention especially […]

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Tuning indexes on RAC environments-2

Globally busy buffers due to contention for index leaf and branch blocks As we discussed in previous sessions, because of batch INSERT high concurrency could occur for a relatively small set of index leaf and branch blocks, where index keys are populated with monotonically ascending values.The symptoms are increased frequencies and wait times for a […]

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Tuning indexes on RAC environments-1

Introduction and Significance of tuning indexes in RAC environments. Oracle E-Business environment with financial modules like AP and GL having large scale payment invoices transaction. Let me take example of one my public sector clients, they do process of 3 million payment instructions every night. Such most insert intensive applications running on RAC the frequency […]

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Index Performance Tuning Techniques for RAC

It’s been quite some time since my readers are requesting to see some posts on RAC performance tuning concepts and practices. In the process of testing some of the tuning techniques, as well as discussing and interpreting the results, I am preparing a four-day in depth session to understand index performance tuning techniques for RAC. […]

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adpatch options

adpatch options Few of our dbas are still not clear about the helpful features of adpatch utility with command line options.If you are in a production downtime to do some patching activity, especially for some rollup upgrade, your downtime will end up with series of pre and post patches. In Such a scenario, it is […]

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Oracle Dictionary – DBA Views – Quick Reference

SQL> SELECT * FROM DICT WHERE TABLE_NAME LIKE ‘DBA_%’ ORDER BY TABLE_NAME; TABLE_NAME COMMENTS —————————— —————————————————————————————————- DBA_2PC_NEIGHBORS – information about incoming and outgoing connections for pending transactions DBA_2PC_PENDING – info about distributed transactions awaiting recovery DBA_ADVISOR_ACTIONS – DBA_ADVISOR_COMMANDS – DBA_ADVISOR_DEFINITIONS – DBA_ADVISOR_DEF_PARAMETERS – DBA_ADVISOR_DIRECTIVES – DBA_ADVISOR_FINDINGS – DBA_ADVISOR_JOURNAL – DBA_ADVISOR_LOG – DBA_ADVISOR_OBJECTS – DBA_ADVISOR_OBJECT_TYPES – […]

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Gather Schema Statistics with LASTRUN Option does not Clean FND_STATS_HIST Table

After running Gather Schema Statistics concurrent request with (LASTRUN) option to save only the history for last run, then run the concurrent request again for 2 times after that found that (FND_STATS_HIST) tables contains the history for all the 3 requests and it is not cleaned up to keep only last run. Sample steps to […]

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Notice to Oracle E-Business Suite Customers: Correction to Export/Import Notes (Doc ID 1055539.1)

If you conducted an import or export of an Oracle10g Release 2 or 11g Release 1 database prior to September 11, 2009, you should follow the instructions in My Oracle Support Knowledge Document 1055539.1 to verify the privileges in your database. This is because a missing step in several OracleMetaLink notes published before 11 September […]

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New patch required after installing PSU 11.1.0.7.1 to ASM environments

An ASM Regression issue has been reported with 11.1.0.7.1 PSU. A Mandatory patch is being recommended to resolve the ASM regression issue. There is very high possibility of running into the ASM regression issue with 11.1.0.7.1 PSU. No action is required if ASM is not being used in the environment Some of the symptoms are: […]

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Are you an Oracle DBA ?

Every DBA needs to know how to do their work under pressure, while facing crisis after crisis. Our most important contribution is to keep the database running. It’s an on-call function; you never know what might happen. Half the branch was up all night last night restoring a database because of a failure. Data recovery […]

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Oracle Support – Useful Metalink References

Patch Set Updates for Oracle Products [ID 854428.1] Quick Guide to Avoid Issues in Creating DB Control Using EMCA [ID 750768.1] Interesting links around Autoconfig in the E-Business-Suite [ID 949160.1] Oracle E-Business Suite Recommended Performance Patches [ID 244040.1] CMCLEAN.SQL – Non Destructive Script to Clean Concurrent Manager Tables [ID 134007.1] Cloning Oracle Applications Release 11i […]

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