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”
Tag Archives: technology
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”
Building a Simple RAG Q&A Assistant with LangChain and OpenAI
I recently explored how to combine LangChain and OpenAI’s GPT models to create an intelligent Retrieval-Augmented Generation (RAG) assistant. This project can read your local documents, store them in a searchable vector database, and answer questions based on your own text . What is RAG? RAG (Retrieval-Augmented Generation) is a powerful technique that combines informationContinue reading “Building a Simple RAG Q&A Assistant with LangChain and OpenAI”
Hello AI, Using OpenAI API with Python
Recently, I tried using OpenAI’s Python library for the first time — and I was amazed at how easy it is to create a conversational AI assistant with just a few lines of code. In this post, I’ll share my experience and a simple Python example that lets you chat directly with GPT right fromContinue reading “Hello AI, Using OpenAI API with Python”
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!”
AI for DBAs: Understanding AI Vectors
Imagine you’re building a robot librarian. Instead of organizing books by titles or authors, it groups them by meaning—romance novels near poetry, tech manuals near science fiction. This is exactly what AI vector databases do: they turn messy data (words, images, sounds) into meaningful numbers that machines can understand. Let’s break it down. 1. AI Vectors: Turning Chaos IntoContinue reading “AI for DBAs: Understanding AI Vectors”
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”
How to patch Exadata PDU
Recently, I collaborated with a colleague to promote our Exadata system to a new Oracle Enterprise Manager (OEM) server. However, we encountered issues when attempting to promote the Power Distribution Unit (PDU). After consulting My Oracle Support (MOS), we decided to address potential bugs by applying the latest PDU patch before proceeding with the promotionContinue reading “How to patch Exadata PDU”
What should we do if the Flash Cache is degraded in an Exadata cell
Flash cache plays a critical role in Exadata performance. When issues arise, it’s crucial to understand the symptoms and resolution steps. Typically, each flash cache comprises four flash disks. If one flash disk fails, the cell service automatically removes it while continuing to operate with the remaining three disks. In most cases, immediate intervention isContinue reading “What should we do if the Flash Cache is degraded in an Exadata cell”
Oracle DBA Insights 