How to analyse Database Growth in DB6 IBM

2495068 - How to analyse Database Growth in DB6 IBM

 

Symptom

• Transaction DBAcockpit - Space - Database shows an increase in DB Growth
• SAP Earlywatch report shows increased Database Growth

Environment

DB2 LUW (Windows, Linux and Unix

Reproducing the Issue

1. Call transaction DBAcockpit - Space - Top Space Consumers
2. Filter by Growth and then by largest table
3. Where you do not see the icon "Top Space Consumers" you can access the same output via the second screenshot below 
4. Call DBAcockpit transaction - Space - History-Tables and Indexes
5. In the selection screen, sort by growth for all Tablespaces and Indexes via (*)
   
   

Cause

• Database Growth due to increased Application data/problematic Application
• The Data Collectors - DBAcockpit - Configuration -Data Collector Framework are not working correctly and
  the history data is not current or correct.
• The table Index size is large
• Where DB2 compression is used there is a problem with Compression.

Resolution

Check the tables which are reported under Top Space Consumers in the SAP Notes.

1. Some Application tables have their own housekeeping and reports which carry out maintenance for specific tables
2. KBA 2388483 - How-To: Data Management for Technical Tables contains details of tables which have specific handling. (Not Application tables)
3. DB2 compression is not used.  
   You can reduce the disk space needed for your DB2 database by using compression.  SAP Note 1555903 - DB6: Supported DB2 Database Features
4. Provides an overview of what types of compression are supported in SAP/DB6 environment.
5. Other tables may contain empty pages and may require a reorganization which can be done via the DB6conv (latest version always) SAP Note 1513862 - DB6: Table conversion using DB6CONV version 6 or higher
6. From 9.7 onwards the 'Reclaimable Storage' attribute of tablespaces to reduce the High-Water mark of the tablespaces was introduced and is automatic.
7. It is not necessary to carry out manual intervention.
   The tablespaces are automatically handled by DB2 and thus when in operation releases space for the OS.
8. As "Reclaimable Storage" is an IBM concept, please refer to the following IBM link for some background.
   The other option is to use the Alter Tablespace Reduce command.
9. DBAcockpit -> Configuration -> Data Collector Framework, all Collectors should have 'Green' Status and SAP Note 1456402 with latest version implemented where applicable to the SAP Basis version.
   In the System Configuration tab under the <SID>, check that the Collector Options are selected. 
10. 

See Also

• SAP Note 1667259 - DB6: Historical data is not displayed
• Where there is an issue with the DBAcockit - Data Collector Framework, DCF Collectors check 
  SAP Wiki:  No Space History in DBAcockpit or DB02 transaction - What to check

Keywords

compression, HWM, High Water Mark, cause, huge, monthly, weekly, reduce database size