Statistics event monitors are an extremely useful way to get periodic monitoring of basic metrics on your system. They're just well-disguised behind a somewhat misleading name.
OVERHEAD and TRANSFERRATE are tablespace parameters that the optimizer uses to help choose an access plan. Are the defaults good enough? (hint: probably not) In this blog post, I describe a simple way to measure values for your system.
Over the course of the past several releases of DB2 for z/OS, IBM has added many features and capabilities that are transforming the platform. This presentation takes a look at the big changes that have been introduced to DB2 including new SQL, universal table spaces, improved security, and more. Th
Tuning of SQL queries requires understanding why DB2 chose a particular access path and determining whether or not that access path should perform as expected. The key to this is understanding what filter factors are, how they are used by the Optimizer and how to get DB2 to better estimate them,
Let’s start this discussion candidly – I am a big fan of the FETCH FIRST n ROWS ONLY clause coded in a SQL statement. That assertion will require some clarification, since there are some valid use cases, and others that make little sense. Regardless, I will try not to over-complicate the discussion.