Oracle 26ai Read-Only Users and Sessions

One very common production request sounds simple:

"Can we give this user access, but make sure they cannot change anything?"

Before Oracle AI Database 26ai, DBAs usually handled this by creating a separate reporting user, granting only SELECT, removing DML privileges, or depending on carefully designed roles. That approach works when access is cleanly designed from the beginning. But in real production systems, users often collect privileges over time. Support users get emergency grants, application users may have broader access than expected, and batch accounts sometimes have privileges that nobody wants to touch during an incident.

PostgreSQL Performance Tuning That Survives Production

    A PostgreSQL performance issue rarely starts with one bad setting.

In production, it usually looks like this: the application team says the database is slow, CPU is not always high, storage graphs look confusing, and nobody changed anything “major”. Then we check deeper and find long transactions, dead tuples, stale statistics, unused indexes, chatty application queries, or checkpoint pressure.

PostgreSQL VACUUM: Bloat, Autovacuum and Real Fixes

    A PostgreSQL table can grow quietly for weeks before anyone notices. The application team says they already deleted old data. Storage still looks high. Queries are touching more blocks than expected. Autovacuum is running, but the table does not seem to become smaller. This is where many DBAs first realize that DELETE in PostgreSQL is not the same as physically removing rows from the table file.

PostgreSQL uses MVCC, so old row versions remain inside the table until VACUUM can clean them. This is normal behavior, not a bug. The problem starts when dead tuples grow faster than VACUUM can remove them, or when long-running transactions prevent cleanup. Then you get table bloat, index bloat, stale statistics, poor plans, unnecessary I/O, and sometimes transaction ID wraparound pressure.

My Oracle ACE Journey: From Practical Sharing to Oracle ACE Pro

  Some journeys do not begin with a plan. They begin with curiosity, consistency, and a simple intention to share what we learn.

My Oracle ACE journey is one such journey.

Recognized Among FeedSpot’s Top 70 Database Blogs to Follow in 2026

I am happy to share that Learn DBA : A Life Long Learning Experience has been selected by FeedSpot as one of the Top 70 Database Blogs to Follow in 2026.

RMAN Restartable Backups Explained for Production DBAs

Most DBAs have seen this at least once. You wake up, check the overnight backup report, and RMAN failed halfway through a 14 TB database backup because the backup filesystem filled up, a network mount disconnected, or one RAC node crashed during the run.

ORA-01017 in RAC 12c and above ? Stepwise Permission Fix & Cause identification

  As an Oracle DBA, few things are more frustrating than a sudden loss of remote connectivity right after a routine SYS password reset. You type in the credentials, and bam -- ORA-01017 greets you, even though your local connections work fine. In production RAC environments, this isn’t just about a mistyped password.

Recently, I faced a tricky scenario in an Oracle 19c RAC setup with proper role separation between the grid and oracle OS users. What seemed like a simple password mismatch quickly unraveled into a multi-layered “permission deadlock,” involving rogue listeners, contaminated IPC sockets, and GPnP directory access issues. It took a careful, stepwise approach to restore connectivity across all nodes without compromising the cluster.

Oracle RAC Load Balancing Internals Explained

 Most RAC clusters look healthy until the workload shifts suddenly.

A reporting job starts hammering one node. Connection pools keep sending sessions to the same instance. CPU climbs, gc waits spike, application response times become unpredictable, and suddenly everyone starts blaming storage, SQL plans, or the network.

But many times, the real problem sits in the RAC connection routing layer itself.

I have seen large RAC environments where all nodes were technically UP, yet one instance was drowning while another sat nearly idle. The cluster wasn’t failing. The load balancing strategy was.

Oracle RAC load balancing is often misunderstood because people assume SCAN alone magically distributes workload intelligently. It does not.

Oracle Data Pump Migrations: What Breaks in Real Upgrades

Most DBAs discover the real complexity of Oracle database migrations only after the first large-scale Export/Import cutover goes sideways. On paper, Oracle Data Pump looks straightforward. Export the database, import it into a newer release, validate the objects, switch applications, done.

Reality is usually messier.

PostgreSQL Backup Guide: pg_dump vs pg_dumpall

 If you have ever been in a production outage where a single schema was corrupted or a developer dropped the wrong table, you already know one thing ; your backup strategy is only as good as your restore flexibility.

In PostgreSQL, logical backups using pg_dump and pg_dumpall are your first line of defense for granular recovery. Unlike physical backups, they give you the ability to restore specific objects, migrate databases across environments, and even troubleshoot data inconsistencies without touching the entire cluster.

Essential Oracle Database Keywords for DBAs - Part 2

When you are preparing for an Oracle DBA interview — or troubleshooting a production issue at 2 AM — definitions alone are not enough. You need clarity. You need context. And most importantly, you need to understand how Oracle behaves under pressure.

When Oracle Uses PGA Instead of SGA for Large Table Scans

Most Oracle DBAs learn early in their careers that the System Global Area (SGA) is the primary memory structure used for caching data blocks. The assumption is simple: data blocks are read from disk, placed in the buffer cache, and reused by future sessions.

However, that assumption doesn’t always hold true in production.

In many real-world workloads , especially analytics queries, reporting jobs, or large batch processing-- . Oracle intentionally bypasses the buffer cache and reads data directly into the Program Global Area (PGA). This behaviour surprises many DBAs when they notice unusual wait events like direct path read, or when frequently queried tables seem to generate repeated disk I/O.

Adding an Instance to Oracle RAC: Step-by-Step Guide for DBAs

 Expanding your Oracle Real Application Clusters (RAC) database by adding a new instance can be intimidating, especially if you want to ensure zero downtime and seamless integration. Whether you're introducing a new node or simply adding an instance to an existing one, the process involves careful planning, configuration, and execution. In this guide, we’ll walk you through every step, from preparing the environment to verifying the new instance’s operation. By the end of this article, you will have a clear understanding of both DBCA and SRVCTL methods for adding instances, best practices for shared storage and network setup, and tips to avoid common pitfalls.

Oracle Utilities for DBAs: Complete Guide to Essential Tools

 Managing an Oracle Database efficiently requires mastering a variety of utilities designed for administration, data movement, performance tuning, and troubleshooting. Whether you’re performing backups, moving data, monitoring performance, or tuning SQL queries, Oracle provides tools to streamline every task. In this guide, we’ll cover the most commonly used Oracle utilities, grouped by functionality, with practical examples and best practices for real-world DBA scenarios.

Understanding Oracle 19c DML Internals for OLTP Performance

For Oracle DBAs managing high-volume OLTP (Online Transaction Processing) systems, understanding how core DML (Data Manipulation Language) operations function under the hood is essential. SELECT, INSERT, UPDATE, and DELETE statements are the backbone of any database, but their internal mechanics—parsing, execution, undo/redo generation, buffer cache interactions, and transaction control—can significantly impact system performance.

Oracle 26ai ASC: Fast Loads Without HCC Pain

 Most DBAs who run large Oracle data warehouses already know the trade-off.

The ETL team wants maximum direct-path load speed because nightly ingestion windows keep shrinking. The storage team wants Hybrid Columnar Compression (HCC) everywhere because storage costs are exploding. Meanwhile, DBAs get stuck in the middle trying to balance ingest performance, archive growth, Smart Scan efficiency, backup footprint, and query response times.

Oracle Backup Success Story : Predictable Backups, Confident Restores - Oracle Features for Modern VLDBs

 When we talk about database growth, we usually celebrate it. But growth without backup redesign is silent risk.

This was the story of a 60.5 TB Oracle production database, where individual datafiles had grown between 500GB to 800GB+, and backups were quietly destabilizing the entire ecosystem.

What started as a "long backup" issue turned into something much deeper.

Essential Oracle Database Keywords Every DBA Should Know - Part 1

 Whether you are just stepping into the world of Oracle databases or have years of experience managing complex environments, understanding the foundational keywords and concepts is crucial. Oracle databases come with a rich ecosystem of terms, from memory structures and wait events to transaction control and performance monitoring. This guide walks you through essential Oracle database keywords, explaining each term in plain language with practical examples. You’ll learn not only what these concepts mean but also how they impact daily database operations, troubleshooting, and performance tuning. By mastering these terms, freshers gain a strong starting point, while seasoned DBAs can refresh and refine their knowledge. 

In this first installment, we cover critical keywords ranging from Buffer, Cache, and Parsing, to Data Pump and SQL Plan Baselines, giving you a solid foundation for Oracle administration.

SQL Query Tuning in Oracle: A Practical Guide for DBAs

 If you're an Oracle DBA, you already know this feeling: a message pops up — “The application is slow.” No context. No logs. Just urgency.

And more often than not, the root cause comes down to a poorly performing SQL query.

SQL tuning in Oracle isn’t just about adding an index or running the SQL Tuning Advisor. It’s about following a structured, evidence-based approach that eliminates guesswork. Over the years, I’ve realized that the biggest difference between average and effective SQL query tuning lies in discipline — knowing what to check, in what order, and why.

Oracle Data Archiving Best Practices Guide

As an Oracle DBA, you already know this feeling - the database keeps growing, storage keeps expanding, backups take longer, maintenance windows shrink, and suddenly performance complaints start coming in.

Handling large data volumes isn't just about adding more disks or increasing SGA. It's about implementing Oracle Data Archiving best practices that balance performance, cost, compliance, and scalability.

How to Boost Oracle Data Pump Performance for Faster IMPDP Operations

 Oracle Data Pump (IMPDP) is a powerful utility for moving data between Oracle databases, but large-scale imports and exports can often be slow and resource-intensive. Whether you’re managing a standalone database or handling complex LOB-heavy schemas, improving Data Pump performance is key to reducing downtime and ensuring smooth operations. In this guide, we’ll explore practical strategies to enhance IMPDP performance, including parallelism, network-based imports, LOB optimizations, and buffer tuning.

VLDB Backup Optimization – RMAN Concepts Revision for Interviews

 

Q 1: What is the main challenge when backing up a multi-terabyte Oracle database with very large datafiles?

Republic Day Reflections for DBAs: Oracle, PostgreSQL, MSSQL, and the Art of Governance

As India celebrates 26th January - Republic Day, it’s a perfect moment for DBAs to draw parallels between national governance and database management. Just as the Constitution defines rules, responsibilities, and structures for our nation, robust databases rely on architecture, policies, and governance to thrive.

Oracle Hybrid Partitioned Tables in Real Systems

 Most large Oracle environments eventually hit the same wall.

The database keeps growing, storage costs climb every quarter, backup windows become unpredictable, and suddenly DBAs are spending more time managing historical data than supporting the actual application workload. 

Usually the first reaction is archive-and-delete.

Then the reporting team complains because last year's data disappeared.

All Important Things About Oracle RAC Every DBA Should Know

  In today's always-on digital world, databases are no longer just data stores—they are the backbone of business continuity. Whether it’s a bank processing millions of transactions per second, a pharma company maintaining regulatory compliance, or an eCommerce platform surviving flash sales, downtime is simply not an option. This is exactly where All Important Things About Oracle RAC become critical for anyone working with enterprise databases.