Scenario – your query is performing poorly. You see DB2 picked an access path that is less than optimal. First you make sure there are appropriate indexes. You look to see if the statement is written in a way that enables DB2 to use those indexes. Then you check the Filter Factors of the predicates.
We all know the importance of avoiding Prepares in dynamic SQL. But performance tuning often involves balancing one cost against another, so are there are times when incurring a Prepare cost is justified in the bigger picture? There might be cases where this is true, but if you don’t measure ...
For the past 30 years, our focus as DB2 for z/OS database administrators has been on the support of COBOL programs with static queries that were relatively easy to control as they were identical throughout the business logic. Static SQL provided persisted access paths in the database s
An under-appreciated set of ANSI SQL functions introduced over a decade ago could dramatically reduce application chattiness and improve response times.
This month’s third article is by John Maenpaa. John provides us with the overview of a real life project. The choice was between JSON, XML and traditional relation structure, in order to store complex forms. John talks about measurements and considerations. This article is a must read.