I’m a Db2 for z/OS Database Administrator with 23+ years of hands-on experience in performance tuning, SQL and index design, data sharing, performance stability during version upgrades and production operations.

For past 10+ years, I optimized 20+ processes each year and cut more than 10,000 CPU hours every year, with no new hardware and no re-architecture. The savings came from SQL rewrites and index changes, found by ranking workloads by total CPU instead of by complaints, rebound safely, and proven with measured before-and-after numbers.

Here I write about what that taught me:

> How to choose which SQL is worth tuning > Real SQL and index fixes, with EXPLAIN before and after > How to rebind packages without access path surprises > How to prove tuning savings to management

I work on Db2 13 for z/OS, using tools such as IBM Query Monitor and Db2 SMF 101 accounting data.