BMC REORG – Build Compression Dictionary inefficiency

Problem:

Application batch job failed with -904 resource (Reason 00D70014) not available due to table space partition reached maximum limit. This job used to do mass insert but the business data volume was as usual and very much below the maximum limit.   

Note: All table space in our application are compressed.

Reason:

On analysis, we found BMC REORG that ran on that particular partition of the table had built a compression dictionary which is not efficient, causing the partition space reach maximum limit.  Found in the same table highest records stored is over 50 Million in a single partition, whereas, due to poor dictionary built in this particular partition caused to it reach maximum space of 4GB  when it had only 42 Million records.

 

Fix:  

Run IBM REORG on the same partition which brought down space usage to 3GB from 4GB limit.

 

Lessons Learnt:

IBM REORG builds better compression dictionary and provided good space saving compared to BMC REORG.


Use BMC Option ORDER YES and KEEP DICTIONARY NO to get similar compression as that of IBM REORG. But you also see increase in CPU usage time and run time.