A request came in on a Thursday afternoon — the UAT team needed a fresh copy of the production PDB by Friday morning for regression testing. We had done local PDB clones before. The command is short, the documentation looks clean, and on a quiet system the operation finishes in minutes. What we had not Read more about PDB Cloning in Production: Gotchas Nobody Warns You About[…]
We had four PDBs on the same CDB running without any Oracle PDB resource plan for CPU and memory isolation. Three of them handled routine OLTP workloads — order processing, user authentication, a reporting schema. The fourth was a batch analytics PDB that ran nightly aggregations across three years of transactional history. For the first Read more about Managing PDB Resources: CPU and Memory Isolation Done Right[…]
Two weeks ago, I dropped a development CDB called TESTCDB on one of our lab servers. The DROP DATABASE command worked perfectly—but that was just the beginning. The server was still littered with configuration files, diagnostic logs, and startup scripts pointing to a database that no longer existed. If you’ve ever run DROP DATABASE INCLUDING Read more about Complete Oracle Database Cleanup Checklist: Remove CDB After DROP DATABASE[…]
Last month, I needed to decommission a development PDB that was consuming valuable storage on our production CDB. The challenge? Ensuring all datafiles were completely removed without affecting other PDBs in the container. If you’ve ever hesitated before dropping a PDB—worried about orphaned datafiles or accidentally keeping files you meant to delete—this guide walks you Read more about How to Drop a Pluggable Database Including Datafiles in Oracle 19c[…]
Last Updated: December 2025 | Oracle 19c/21c | By Ahaaryo Oracle Version Scope: This guide covers Oracle 19c (fully supported) and Oracle 21c (Innovation Release, already desupported but widely deployed). Introduction “The password is definitely correct!” – Every DBA has said this at least once while troubleshooting ORA-01017 invalid username password. I remember a production Read more about ORA-01017: Invalid Username/Password – Complete Guide[…]
Last Updated: December 2025 | Oracle 19c | ASM Grid Infrastructure Migrating an Oracle 19c CDB from local storage to ASM has six viable methods — and choosing the wrong one means unnecessary downtime or a failed rollback. This guide documents the complete migration of a production CDB with one PDB: datafiles, controlfiles, redo logs, Read more about Migrating Oracle 19c Database from Local Storage to ASM: A Complete Step-by-Step Guide[…]
Last Updated: December 10, 2025Tested On: Oracle Enterprise Linux 9.5, Oracle ASM 19c Patch 25 CRS-4535: Cannot communicate with Cluster Ready Services. That error at 2 AM — after a reboot — means ASM didn’t come up. Which means your databases didn’t mount. Which means your phone doesn’t stop ringing. This guide walks through Oracle Read more about Oracle ASM 19c Installation: Complete Guide to Oracle Restart Grid Infrastructure [2025][…]
Introduction Need to enable archive log mode in Oracle 19c but unsure of the exact steps? Converting from NOARCHIVELOG to ARCHIVELOG mode is essential for production databases, yet many DBAs hesitate due to concerns about downtime and configuration complexity. In this guide, I’ll walk through the complete process of enabling archive log mode in Oracle Read more about How to Enable Archive Log Mode in Oracle 19c (Complete Guide)[…]
There are times when you require to drop your existing database for more than one reason. Dropping a database is not a tough job at all, if you are very sure that which database you should drop. Originally written for Oracle 11g. The DROP DATABASE command syntax and prerequisites remain the same in Oracle 12c, Read more about Drop a database[…]