Oracle Indexes: Fix Slow SQL Without Overdoing It

A SQL query running for 8 seconds may not create panic during testing. In production, the same query can become a real incident when it runs thousands of times from an application, report, or batch process.

I have seen queries drop from seconds to milliseconds after adding one correct index. I have also seen OLTP systems become slower because every column was indexed without understanding the workload. Both situations are common.

Indexes are powerful, but they are not free. They reduce unnecessary reads for SELECT queries, but they add cost to INSERT, UPDATE, DELETE, storage, statistics gathering, and maintenance. A good DBA does not create indexes blindly. A good DBA checks the SQL pattern, data volume, selectivity, execution plan, and write workload before touching production.

Oracle 26ai AWR Enhancements for DBAs

 AWR used to be simple when most databases were single-instance, single-tenant, and all important workload stayed on the primary database.

That world is mostly gone.

Today, one CDB may host multiple PDBs. Reporting may run on Active Data Guard. Read traffic may be pushed toward True Cache. Replication may be handled through GoldenGate or XStream. When performance breaks, the first question is no longer just “what was the top wait event on the database?”

DB Time vs CPU: The Metric Most DBAs Ignore

 If you have worked in production environments long enough, you have probably seen this situation before. An alert fires in the middle of your daily shift appears.. as "CPU is at 90%. The database must be overloaded." 

Infrastructure teams immediately start discussing scaling CPU, adding cores, or moving the database to a bigger server. But experienced DBAs know something important: High CPU utilization does not automatically mean the database is the bottleneck.

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.

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.

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.

Why Oracle Execution Plans Suddenly Change

 A query that normally runs in under a second suddenly starts taking 20 seconds after midnight maintenance. CPU spikes. Application teams report slowness. Storage looks healthy. Nothing obvious changed in the SQL itself.

In many Oracle production incidents, the real culprit is not the query. It is the execution plan.

Oracle's optimizer constantly evaluates how SQL should execute based on statistics, metadata, bind values, memory conditions, and optimizer behaviour. The same SQL can behave very differently depending on what Oracle believes is the cheapest execution path at parse time.

Oracle Cursors and the Hidden Cost of Parsing

 Some Oracle performance problems announce themselves loudly with blocking sessions, failed jobs, or storage alerts.

Cursor-related issues usually do the opposite.

The database slowly becomes inconsistent. CPU rises during peak hours. Application response time fluctuates. AWR reports start showing library cache waits and excessive parsing activity even though the SQL itself does not look particularly heavy.

Oracle Index Rebuild: When It Really Makes Sense for Performance Tuning

Index maintenance is a hot topic among DBAs .. that too, especially when it comes to performance tuning. Rebuilding indexes can feel like a magic bullet but, in reality, it’s rarely needed and often overused. In this article, we will cut through the noise, explain when rebuilding makes sense, and give you actionable criteria and examples to decide confidently whether to rebuild, coalesce, or leave indexes alone.

A Step-by-Step Guide to Identifying and Resolving Performance Bottlenecks

  When it comes to managing an Oracle database, performance issues can be a significant challenge. The Oracle performance methodology is a structured approach designed to help you identify and resolve these issues effectively. This process involves pinpointing bottlenecks within your system and addressing them systematically to improve overall performance.

Mastering SQL Performance with SQL Plan Management

  In my previous blogpost, we delved into the complete details on loading a SQL Plan with its Plan Hash Value.  SQL Plan Management (SPM) is a powerful feature designed to ensure consistent and optimized SQL performance by managing execution plans proactively. By leveraging SQL Plan Baselines, SPM helps maintain query efficiency and reliability, making it an essential tool for database administrators. Here's a closer look at how SPM works, its benefits, and its role in maintaining SQL performance.

Oracle - A Quick-Action Guide for Performance Issues

 In the world of application management, performance issues are inevitable. While you might have a solid methodology for establishing and improving application performance, emergencies demand a different approach. When a system suddenly shifts from being reliable and predictable to sluggish and unresponsive, immediate action is required to restore normal service.

Addressing Client-Reported Slowness: A DBA's Guide

 As a Database Administrator, you’re often called upon to troubleshoot performance issues reported by clients. In continuation to my previous blogpost here is an another post in same topic. 

These issues generally fall into three categories:

Unlocking Oracle Hints: Practical Insights for Developers

 Oracle hints are like secret codes that can transform your SQL queries, guiding the optimizer to craft the most efficient execution plans. When used wisely, these hints can lead to significant performance gains, making your applications run smoother and faster.

In this post, we’ll explore some essential Oracle hints, complete with practical examples that you can start using right away.

Effortless Optimization: All about Oracle's Auto Maintenance Tasks

  Auto maintenance tasks are those little helpers that keep your Oracle database running smoothly without any manual intervention. These tasks kick in during maintenance windows, ensuring your database stays healthy and optimized. Here’s a closer look at these automated maintenance superheroes..

Load a SQL Plan with its Plan Hash Value into SQL Plan Baseline

 As a seasoned database administrator, I’m no stranger to the quirks and challenges of maintaining a high-performing database environment. Recently, I encountered a situation that many of you might find familiar: the need to load a specific SQL execution plan into a SQL Plan Baseline using its plan hash value. Let's dive into this topic and unravel the steps together, adding a sprinkle of fun along the way!

DBA's Guide to Troubleshooting Database/Query Performance Problems

When DBAs receive a performance issue incident, the first step for DBA is to gather as much relevant information and background as possible. To do this, ask users or developers the following preliminary questions to collect initial data:

Let's Trace! Dive into SQL Tracing

 Let’s get into the world of tracing, Find ways to uncover mysteries and optimizing performance along the way using sessions and tracings.

Unlocking Advanced Oracle Diagnostics: A Guide to Installing SQLT

   SQLT aids in diagnosing SQL statement performance problems by collecting and analyzing detailed trace data.