As a database administrator you want your database to achieve top performance. This topic provides basic maintenance recommendations for installations with DB2 databases.
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Reorganize the Automation Engine database (including all Clients) on a regular basis.
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Do not limit resource consumption. Aborting transactions due to limitations specified in the database hamper processing in the AE system. Additionally, inconsistent database contents can occur which cause subsequent errors or endless loops.
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Statistics in DB2:
- Turn off automatic runstats (every version) and run runstats manually at a point in time where a typical load and a typical mix of activities are in the system.
- Never run runstats when no or only a few activities are present. This would lead to wrong/not optimal access plans and therefore to less throughput or in the worst case to deadlocks.
- If you encounter deadlocks, run runstats exactly on those tables where the deadlocks occurring, and at a point in time when you have deadlocks. In most cases this will solve the deadlocks.
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Make sure to have the tables dimensioned big enough when creating the database. As the sizes depend on the actual use of AE, the following overview shows the right span of sizes in percent:
- RT: 40% - 60%
- AH: 20% - 30%
- ABLOB: ~ 19%
- MELD: 10% - 20%
- AJPP: 5%
- RH: 5%
- Other tables: < 1%
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Reorganize indexes on a regular basis.
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DB2 on UNIX/Windows:
Default settings are optional for the supported DB2 versions. Changing these values does not improve performance. Storing the database LOG areas on a high-performance disk is strongly recommended.
See also: