ITPUB

Oct 10, 2016 · Databases

How to Reclaim Oracle High Water Mark Space and Boost Query Performance

This guide explains the concept of Oracle High Water Mark (HWM), why it grows with DML operations, and provides a step‑by‑step procedure—including pre‑check, shrink space, and post‑check—to reclaim unused blocks, reduce tablespace usage, and improve scan efficiency.