IDUG EMEA 2026

Db2 utilities are fundamental to database availability, performance, and recoverability—yet many sites treat them as black boxes.
This session explores the internal behaviour of key Db2 z/OS utilities such as REORG, RUNSTATS, COPY, and LOAD. We examine how these utilities interact with data, logging, locking, and system resources, and how understanding their internals helps DBAs run them more efficiently and safely.

Description:
How Db2 utilities really run
How Db2 utilities use buffer pools, logging, IRLM, and the catalogWhy utilities should be treated like normal Db2 work, not background jobs
REORG utility explained
What happens during each REORG phase: unload, sort, reload, rebuild, and switchHow REORG affects locking and loggingWhen REORG improves performance and when it provides little or no benefit
RUNSTATS and the optimizer
Difference between table statistics and index statisticsHow histograms and sampling influence query plansWhy the timing of RUNSTATS matters for access pa