There are several scenarios with DB2 where we need to know what the “worst-case” row length is. That is, if all varying fields are completely full and any LOBs are maximally inlined, how much space could a single row actually take up?… Read the restContinue reading »
What is ADMIN_MOVE_TABLE
ADMIN_MOVE_TABLE is an administrative stored procedure introduced in DB2 9.7. The intent is to provide a tool that can be used to perform an online move of a table, while transactions are still occurring against the table. Moves can be used to change what tablespace a table is in, convert a table to MDC, change the table name, perform several changes that would normally require reorgs, reduce the size of a column, and perform other changes.… Read the restContinue reading »
I have been paying a bit of attention to cross-platform SQL optimization lately, and read this interesting post:
Being a bit of an experimenter, the first thing that I wondered is how DB2 would handle this scenario. Would the DB2 optimizer be smarter than others, or would the same hold true for DB2 that held true for PostgreSQL?… Read the restContinue reading »
I actually had a blog entry started on this topic before IDUG. I knew this was possible, but not exactly how to do it. Then I sat in Scott Hayes’ session – D04 – More Sage Advice: Invaluable DB2 LUW Performance Insights from Around the Globe, and he had all the details I needed to really get rolling on trying this out – saving me valuable time in research.… Read the restContinue reading »
When you’re considering dropping and re-creating a table, view, or MQT, it is critical to ensure that you consider any dependencies. When dropping a table, any MQTs that rely on it will be dropped, and views marked inoperative. With multiple levels, it can be difficult to Identify everything.… Read the restContinue reading »
I’ve played with the clpplus at least once before, but have generally thought of it as a tool created to satisfy those coming from Oracle and looking for Oracle-like features. One of the features I actually liked about Oracle in the class and certification tests that I took for it was the ability to specify values for an SQL statement stored in a file on execution.… Read the restContinue reading »
Current statistics are vital to performance. If I’m encountering a database I haven’t regularly been supporting, and don’t know the maintenance plans and schedules, I frequently query to get an idea of how current they are.
To report the dates of statistics collection and the number of tables statistics were collected for on each date.… Read the restContinue reading »
I wrote a developerWorks article on finding problem SQL in your package cache. But I refine and play with my SQL over time, so I thought I’d share the version I’ve been using recently.
To find problem SQL in the Package Cache across several importance performance categories.… Read the restContinue reading »