This will hold all blog related to Oracle Database
Every organization running an Oracle production database has a backup. Not every organization has a backup strategy. That distinction sounds subtle. It is not. A backup is a scheduled job and a storage location. A strategy is a set of deliberate decisions — what to back up, how much of it, how fast it needs Read more about 5 Key Considerations for Your Oracle Database Backup Strategy[…]
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[…]
Three weeks before go-live on an Oracle AI Database 26ai deployment, we ran a readiness review mostly with the help of Oracle AI Database 26ai production DBA checklist. At the surface level, things looked stable. Vector search was working in staging. JSON Relational Duality Views were serving the REST layer. Select AI was configured against Read more about Building an AI-Ready Oracle Database: A Production DBA Checklist[…]
A developer on our team sent a message last week: “Is there a way to just ask the database how many Critical errors are in the Memory category without writing SQL?” He had heard about Oracle Select AI 26ai and wanted to know if it was live on our instance. That question is exactly the Read more about Select AI: Talking to Your Database in Plain English[…]
Last month we were reviewing a staging incident where an application team had migrated their REST layer to use JSON Relational Duality Views in Oracle AI Database 26ai. The feature worked exactly as advertised during unit testing — clean JSON in, clean JSON out, relational tables staying normalized underneath. Then they ran a load test Read more about 5 Things DBAs Must Know About JSON Relational Duality in Oracle AI Database 26ai[…]
We have run vector search workloads on both Oracle AI Database 26ai and PostgreSQL with pgvector and we are here to show you the architectural breakdown of Oracle AI Database 26ai vector search vs pgvector. The technical capabilities of both are real — pgvector works, and PostgreSQL shops have built production vector search on it. Read more about Oracle AI Database 26ai Vector Search vs PostgreSQL pgvector — A DBA’s Perspective[…]
We had a support tool prototype running vector search against an Oracle error knowledge base. Pure semantic search — query comes in, top five similar errors come back. Worked well in testing. In production, the first complaint arrived within a week: “It keeps returning memory errors when I search for connection problems — they are Read more about Hybrid Search in Oracle AI Database 26ai — Combining SQL and Semantic Queries[…]
In the life of an Oracle Database Expert, It usually early morning when the monitoring alert fired. Typically 3 AM in then morning, applications throwing ORA-04031, Developers calling and the on-call DBA logged in to find the shared pool exhausted — Oracle unable to allocate a single new object in memory. No new SQL could Read more about ORA-04031: Shared Pool Exhaustion — Root Cause and Fix[…]
In Post -2 of this series, We had a vector search query running clean in development — ten milliseconds, HNSW index in the plan, results looking right. The moment the same query hit a table with eight million rows in staging, response time jumped to forty seconds. The execution plan had quietly switched to TABLE Read more about Vector Indexes in Oracle AI Database 26ai — How HNSW and IVF Work Under the Hood[…]
In Post 1 we established the architecture — Oracle 23ai puts vector search inside the database engine, not in a separate system. We titled that post using “23ai” deliberately — because that is the name most production DBAs are still searching for, still referencing in upgrade discussions. Since then, Oracle announced Oracle AI Database 26ai Read more about Oracle Vector Search: Your First Hands-On Walkthrough[…]
A few months ago, we were in an architecture review when the solutions architect put up a slide titled “AI Stack — Proposed.” Oracle was in the middle tier, doing what it always does — transactions, reporting, the core workload. Sitting beside it, in its own separate box, was a vector database. Pinecone, specifically. The Read more about Oracle 23ai — Why Oracle Calls It The AI Database[…]
By Sanjeeva Kumar | Senior Oracle DBA | Oracle ACE Apprentice | dbadataverse.com Have you ever looked at an Oracle version string and struggled to figure out exactly when it was released? You are not alone. Recently, while reviewing patch compliance across our Oracle 19c production environments, a colleague asked a simple question — “Are Read more about Oracle 26 AI Version Numbering: What Does 23.26.1.0.0 Actually Mean?[…]
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[…]
Introduction Have you ever been asked to explain why your Oracle database was slow last Tuesday at 2:30 PM? Or needed to identify which SQL statements were causing CPU spikes during last night’s batch run? This is where DBA_HIST_ACTIVE_SESS_HISTORY becomes your most powerful diagnostic tool. Recently, we faced a production issue where users reported intermittent Read more about DBA_HIST_ACTIVE_SESS_HISTORY: Complete Guide to Oracle ASH Analysis[…]
The Problem: TNS-12541 and Database Connection Failures You’ve just installed Oracle 19c on your server. The database is up and running perfectly—you can connect locally using SQL*Plus without any issues. But the moment you try connecting from a remote application or another server, you’re hit with the dreaded TNS-12541: TNS:no listener error. Sound familiar? This Read more about How to Configure Oracle Listener for Standalone Database: Step-by-Step Guide[…]
The Problem: Long-Running Query Fails with ORA-01555 You’re running a critical report or data export, and after 30 minutes it fails with: When this happens: The query was working fine yesterday. The data hasn’t changed much. But today it fails with ORA-01555. This guide shows you exactly how to fix it permanently. What is ORA-01555 Read more about ORA-01555: Snapshot Too Old – Complete Fix Guide for Oracle 19c[…]
The Problem: Cannot Connect to Oracle Database You’re trying to connect to your Oracle database and you get this error: When this happens: You check the database – it’s running. You check the listener – it’s up. But nothing connects. This is ORA-12154, and it means Oracle can’t find or read your TNS configuration. Let Read more about ORA-12154: TNS Could Not Resolve the Connect Identifier – Complete Fix Guide[…]
Last Updated: December 2025 | Oracle 19c | ASM Grid Infrastructure Have you ever encountered a frustrating situation where your Oracle database is running on local storage, and you need to migrate everything to ASM (Automatic Storage Management) without significant downtime? Recently, we faced this exact scenario with a production Oracle 19c Container Database (CDB) Read more about Migrating Oracle 19c Database from Local Storage to ASM: A Complete Step-by-Step Guide[…]
Introduction Have you ever encountered a situation where your Oracle database suddenly stops accepting new connections, and users start complaining that the application is down? One of the most common culprits behind this scenario is the dreaded ORA-00257: archiver error. Recently, we faced this exact scenario with one of our production databases during a high-transaction Read more about ORA-00257: Archiver Error Connect Internal Only Until Freed – Complete Resolution Guide[…]
Last Updated: December 10, 2025Tested On: Oracle Enterprise Linux 9.5, Oracle ASM 19c Patch 25 Oracle Automatic Storage Management (ASM) provides a robust storage management solution for Oracle databases. In this comprehensive guide, we’ll walk through ASM 19c Installation (patch set 25) in a standalone “Oracle Restart” grid infrastructure configuration on Oracle Enterprise Linux (OEL) Read more about Oracle ASM 19c Installation: Complete Guide to Oracle Restart Grid Infrastructure [2025][…]
Introduction Response file for Oracle ASM Standalone is a critical thing to understand if you want to install this using CLI. This blog shows how to install Oracle 19c Grid Infrastructure in standalone (Oracle Restart) mode using a response file from CLI without any GUI. This is particularly helpful for DBAs working on headless servers Read more about Response file for Oracle ASM Standalone Oracle 19c[…]
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)[…]
Introduction Database memory management is crucial for maintaining optimal performance in Oracle databases. Inefficient memory usage can lead to slower query execution, increased I/O operations, and poor application response times. This comprehensive guide provides database administrators and developers with practical tools and techniques for monitoring and optimizing Oracle database memory components. Why Memory Monitoring Matters Read more about Oracle Database Memory Monitoring Guide[…]
The Problem: Data Pump Import Fails with Date Format Error You’re running a Data Pump import and it crashes with date format errors like ‘1998-01-01 00:00:00′. You try setting export NLS_DATE_FORMAT=’YYYY-MM-DD HH24:MI:SS’ in your shell, but the import still fails. Error you’re seeing: This happens because Data Pump doesn’t always respect environment-level NLS settings, especially Read more about How to Export NLS_DATE_FORMAT in Oracle: Data Pump Import Date Format Fix[…]
Have you ever encountered a frustrating situation where your Oracle Enterprise Manager couldn’t monitor your ASM environment, leaving you blind to storage issues? Recently, we faced this exact scenario with a client’s production ASM cluster, and ASMSNMP user comes to rescue. The ASMSNMP user plays a crucial role in Oracle ASM (Automatic Storage Management), primarily Read more about ASMSNMP User Setup: Complete Oracle ASM Monitoring Guide[…]
Introduction Encountering, ORA-65177 ,a Pluggable Database (PDB) that opens in RESTRICTED mode can cause operational challenges, especially when working in a multitenant environment. This issue is often linked to synchronization failures between the Container Database (CDB) and its associated PDBs. We will delve into the root cause of the problem and provide a step-by-step resolution. Read more about Resolving Pluggable Database (PDB) Opening in RESTRICTED MODE (ORA-65177) in Oracle 19c[…]
In our previous blog, we talked about the optimizer access path. Over the last few blogs, we have walked through different access paths one by one. In this blog, we will see how the index unique scan works — and why it is the most efficient index access path Oracle has to offer. Index unique Read more about Optimizer Access Paths: index unique scan[…]
An index fast full scan reads the entire index as it is i.e. as it exists on the disk. This index read is unsorted. This access path usage multiblock IO to perform the index scan. Index fast full scan simply reads all of the leaf, branch and root block of index quickly using multiblock IO Read more about Optimizer Access Paths : Fast Full Scan[…]
Have you ever wondered why some of your Oracle queries bypass the buffer cache entirely and read data directly from disk? Recently, we encountered this exact scenario while investigating performance issues in a data warehouse environment, and I wanted to share our findings about Oracle’s direct path read mechanism. Oracle Direct Path Read is a Read more about Oracle Direct Path Read: Complete Performance Guide with Real Examples[…]
A production AWR report flagged a query with an INDEX FULL SCAN operation consuming significant I/O. The developer assumed it was an index range scan gone wrong. It was not. The optimizer had a reason — and understanding that reason is what separates reactive troubleshooting from deliberate tuning. This post breaks down what Oracle index Read more about Oracle Index Full Scan: How It Works and When the Optimizer Uses It[…]
Distinct is the keyword that oracle used to filter out unique values from a column. However, it is very interesting to see the behavior followed by the optimizer for its access path. How Oracle Index Fast Full Scan Handles DISTINCT Queries? In this “Optimizer Access Paths” blog, we will see how we can make optimizer Read more about Optimizer Access Paths: How Index FFS works with Distinct[…]
In this blog, we will explore what is the access path in the Oracle database. However, before moving to the access path, let’s first understand what is a row source. It is a set of rows that are returned in a step by execution plan. It can be a table or a result of join operations Read more about Optimizer Access Paths: How oracle database works[…]
With its inception in 2006, Amazon AWS has definitely gone a long way. Engineers from Amazon worked really-really well which has not only completely changed the horizon of cloud but also emerges as one of the boon for any business to adopt. Although, there are many other vendors available in the cloud market and they Read more about Cloud database war: Advantage shifting to Red?[…]
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[…]
Problem Statement: Restore entire database using Data Pump. Restore table(s) Restore tablespace(s) Restore schema(s) Restore using Transportable tablespaces (TTS) Restore from multiple small sizes of dump files Restore in parallel mode Originally written covering Oracle 11g/12c Data Pump. The impdp command syntax and parameters remain valid through Oracle 19c and 21c. Newer versions have added Read more about Data Pump: impdp[…]
Introduction Have you ever needed to analyze Oracle database growth trends but found yourself limited by current snapshot data? In real production environments, tracking database growth trends is a critical aspect of DBA life because this allows businesses not only to foresee the real position in terms of existing hardware but also enables planning future Read more about DBA_HIST_SEG_STAT: SQL Queries to Track Oracle Growth[…]
Problem Statement: Backup entire database using Data Pump. Backup table(s) Backup tablespace(s) Backup schema(s) Backup using Transportable tablespaces (TTS) Generate multiple small sizes of dump files Backup in parallel mode Approach: There are single shot solution to all the above problem statement and it is Data Pump. It is one of various backup tools provided Read more about Oracle Data Pump: expdp & impdp[…]
Among various techniques of backing up your database Oracle provides data pump as one of tool which they are constantly improving and making this tool sharper release by release. Data Pump was introduced in Oracle 10g as a replacement for exp/imp. This post covers the concepts that remain valid through Oracle 19c and 21c. For Read more about Data Pump: a tool to backup and restore database[…]
Problem statement: How to move data files from one location to another on same storage. How to move data files from one storage to another. How to rename data files to make data file name standardized Environment / Scenario: You have a database where you have to move your data files from old slower storage Read more about How to re-organize your data files of a tablespace[…]
Updated for Oracle 19c — March 2026 Problem statement: How to migrate huge data from One DB to another DB. Multi-Terabyte data loaded on one database should be copied to another database. Environment: You have multi-terabyte Database Your database is growing on daily basis, based on data feeds. Number of Indexes on these tables are Read more about How to copy Multi terabyte data to another Database Server[…]
Problem Statement: Move DB with Oracle Binaries on New Storage Create new DEV/UAT from Production. Scenarios: While creating new UAT or DEV from production and make this version of oracle to the same patch set level as of production, there are more than to move DB with Oracle Binaries. Examples: One way to move DB Read more about Move DB with Oracle 11g Binaries[…]
We have written blogs which helps DBA doing their day to day works. This blog will explain how to Speed up Inserts while loading data from huge files. Problem Statement: The problem statement this blog is going to answers with respect to Speed up Inserts are: How to speed up loading millions of rows from Read more about How to: Speed up Inserts in database[…]