Performance tuning of BLU databases is an evolving topic at this time. For BLU databases, sort memory cannot be tuned by STMM, and so must be manually tuned.
These statements calculates the buffer pool hit ratio for both BLU and non-BLU activity. This post includes three SQLs – for calculating at the database, bufferpool, and tablespace level. The separate BLU calculations are not yet included in sysibadm.bp_hitratio as of the writing of this article.
This statement reports how selective at the column level queries are that run against a specific table. This does not look at overall selectivity or row selectivity. It will only work in DB2 10.5. BLU performs best when not all columns are referenced by queries.
This statement calculates the compression ratio for BLU tables. The compression ration can be used to help identify tables where compression is not optimal and you may need to look into why. Compression is critical to optimal performance on BLU.
I thought I’d share some issues with STMM that I’ve seen on Linux lately. I’ve mostly been a fan of STMM, and I still am for small environments that are largely transaction processing and have only one instance on a server.
I’m a control freak. I think that control freaks tend to make good DBAs as long as they don’t take it too far. My position for years has been that I would rather control my runstats, reorgs, and backups directly than trust DB2’s automatic facilities. But I also try to keep an open mind. That means that every so often I have to give the new stuff a chance. This blog entry is about me giving automatic maintenance a try. I am NOT recommending it yet, but here’s how I approached it and what I saw.
Working with BLU has been a glorious learning experience for me. I say that both truly with excitement and with frustration. Whenever I have a DBA-character building experience, I’m bound to share it with my readers.
We DBAs are lazy in some ways. Our favorite way of moving large amounts of data is the backup utility. It’s so easy to move data, structure, objects, permissions, etc. But as quick, easy, and efficient as it is, it cannot handle some situations – like skip-level upgrades, data movement between different operating systems, and of course between different RDBMSes.
BLU has been all the hype for DB2 for the past year or more. What exactly is DB2 BLU? How does it work? What do you need to consider before jumping on the bandwagon?