If you recently moved from Oracle 19c to Oracle 23ai, you might find your file replication has stopped. Your status shows “Stopped”, and no matter how many times you try to start it, nothing happens. The Problem: The “SCAN” Name In the old version (19c), replication usually connected directly to a specific server’s name orContinue reading “ACFS Replication Background Process Stopped After Upgrade to 23ai”
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Deinstalling Oracle Grid Home in Oracle 23ai: Step-by-Step Guide
In Oracle 23ai, the procedure for deinstalling an Oracle Home or Grid Infrastructure Home has not changed compared to previous releases. The standard deinstall utility is still used, and the process remains straightforward. In this article, I will walk through the real procedure I followed to remove an Oracle Grid Home in Oracle 23ai andContinue reading “Deinstalling Oracle Grid Home in Oracle 23ai: Step-by-Step Guide”
Out-of-Place GI Patching Using gridSetup.sh in Oracle 23ai / 26ai
Before performing Out-of-Place Grid Infrastructure (GI) patching, it is strongly recommended to read the following MOS document: Step by Step Out of Place Grid Infrastructure Patching Through gridSetup.sh in Silent Mode(Doc ID 2853839.1) Although this MOS document was written for GI 19.x, it is still largely applicable to Oracle 23ai / 26ai. However, the documentContinue reading “Out-of-Place GI Patching Using gridSetup.sh in Oracle 23ai / 26ai”
Partitioning in PostgreSQL vs Oracle
A customer who had migrated from Oracle to PostgreSQL several years ago recently reported a serious performance regression. A critical table—now holding over 700 million rows—had become extremely slow when filtering by date. As an DBA, I approached this from an Oracle perspective: partition pruning, local indexes. PostgreSQL partitioning is broadly similar to Oracle’s, butContinue reading “Partitioning in PostgreSQL vs Oracle”
When the Clustering Factor Strikes: How a “Perfect” Plan Turned into a 9-Second I/O Nightmare
This wasn’t a theoretical exercise—it was a real-world performance issue that left the database paralyzed.Let’s start with the global stats: The database wasn’t working—it was waiting.Over 90% of the query’s elapsed time was spent on I/O waits, meaning the database was stuck reading data from disk. Step 1: The Execution Plan At first view, theContinue reading “When the Clustering Factor Strikes: How a “Perfect” Plan Turned into a 9-Second I/O Nightmare”
Resizing an ASM Diskgroup on Exadata When OCR/Voting Files Are on It
When you try to shrink an ASM diskgroup that holds Oracle Clusterware files (OCR and voting disks), you may hit errors like: Why it happens Even though Oracle bugs 24568147 and 37688474 mention fixes in newer releases (19.27 RU+), this issue still reproduces in 19.28 and 23.8. The voting files are persisted in the ASMContinue reading “Resizing an ASM Diskgroup on Exadata When OCR/Voting Files Are on It”
Be Careful: EX80 Issue Can Wipe Out Your Exadata/ZDLRA X8/X9 Data!
Recently, our ZDLRA X8-2 was impacted by the EX80 issue, resulting in the loss of three disks within a very short time. Two of these disks were partner disks, causing the DELTA disk group to unmount and all customer data to be lost. Oracle Support confirmed that recreating the DELTA disk group was not anContinue reading “Be Careful: EX80 Issue Can Wipe Out Your Exadata/ZDLRA X8/X9 Data!”
How to fix “DROPPED” griddisk in Cell
You may encounter a situation where a grid disk is in a dropped status in oracle exadata cell storage. This issue can be identified using the following command: Additionally, the ASM alert log may show errors like: This error indicates that the grid disks do not have the same size, which is causing issues inContinue reading “How to fix “DROPPED” griddisk in Cell”
Unlocking Performance with Oracle 23AI’s True Cache
Oracle 23AI introduces a groundbreaking feature called True Cache, which provides an in-memory caching layer for frequently accessed data. This significantly improves read performance, especially in environments where quick access to repetitive data queries is critical. However, don’t confuse it with the “In-Memory” feature, as both serve very different use cases. Let’s explore the details.Continue reading “Unlocking Performance with Oracle 23AI’s True Cache”
Benefits of Zstandard Compression in Oracle 23ai HCC
In Oracle Database 23ai, significant improvements have been made to Hybrid Columnar Compression (HCC), with the default compression method now utilizing Zstandard (Zstd) instead of the previous algorithms, zlib and bzip2. But what exactly is Zstandard, and how does it differ from zlib and bzip2? Zstandard is a lossless data compression algorithm developed by YannContinue reading “Benefits of Zstandard Compression in Oracle 23ai HCC”
Oracle DBA Insights 