Edited 12/13/2017 to correct image and details about the database heap. Db2 memory management is a complex topic that I’ve already written about from several perspectives, and have a few blog entries in mind to explore further. A presentation that…
In DB2 9.7, IBM changed the format of table spaces to be “reclaimable”. This has a ton of advantages, but conversion is ridiculously painful. Why Was the Format Changed? Previously, row addresses (referenced in indexes) were relative to the beginning…
If you’re not familiar with MONREPORT, see my DB2 Basics entry on MONREPORT first. Most of the references I’ve seen to customizing the MONREPORT module basically say “get the code out of the database, modify it, and deploy it”. (see…
Edited 11/13/2014 to be more specific about coordinator agents. This is the first in a series of blog entries talking about DB2 internals. I have no intimate knowledge from IBM of how DB2 works internally, just years of watching presentations…
One of the most frustrating things a DBA can experience is troubleshooting due to bad data. The client is upset because rows are missing or incorrect data is returned. The client facing web front end could be displaying gobilty-gook because…
What a Commit is Database management systems have the concept of a commit. This concept has to do with grouping sets of actions together such that they all succeed or fail as a group. This represents the A in the…