Lock-Free Reservations in Oracle 26ai: Comparing Traditional Locking and High-Concurrency Transactions

 

Introduction

Handling concurrent updates has always been a challenge in high-volume transactional systems. Consider a banking application where hundreds of transactions attempt to credit or debit the same account at the same time. With traditional row-level locking, once one session updates the account balance, other sessions must wait until the transaction commits or rolls back. As concurrency increases, this waiting can become a bottleneck, resulting in lock contention, increased response times, and events such as enq: TX - row lock contention.

One of the newer Oracle features designed to address this problem is Lock-Free Reservations. Instead of relying on immediate row locking for certain numeric updates, it allows concurrent transactions to reserve resources while preserving transactional consistency.

In this article, I will compare traditional row-level locking with Lock-Free Reservations using practical examples and see how each approach behaves under concurrent load.

This article is part of a small series on modern concurrency features in Oracle 26ai, including Lock-Free Reservations, transaction prioritization, and value-based concurrency control.

Real-World Oracle OCI PDB Refresh: Solving Clone Performance Bottlenecks Across Peered VCNs

 

Introduction

Recently, I had a task to refresh our UAT environment using a PDB from the production database hosted in Oracle Cloud Infrastructure (OCI).

At first, the activity looked straightforward. The plan was to perform a remote PDB clone from Production to UAT. However, there was one challenge from the beginning: the source and target databases were located in different OCI VCNs.

After establishing connectivity between the environments, I started the cloning process. The clone started successfully, but after approximately one hour, it appeared to stall, and no significant progress was observed.

After some investigation and testing, I identified two important factors that affected the cloning process:

• The target DBCS was running with only 1 OCPU.
• The production database had an hourly archive log backup and a delete job running through Commvault.

In this article, I will share the architecture, troubleshooting process, and lessons learned from this refresh activity.

Cross-Version Oracle Database Automation on Oracle Linux (7, 8, 9) with systemd, dbstart/dbshut, and Email Alerts on Failure

 

Introduction

In Oracle environments that do not use Oracle ASM, databases are not configured to start automatically after a server reboot. To automate database startup and shutdown, administrators commonly use Oracle's standard dbstart and dbshut utilities.

Although these tools provide basic automation, they do not always verify that the database has successfully reached the OPEN state, and they do not provide built-in notification when startup failures occur.

This article demonstrates how to combine dbstart/dbshut, systemd, startup validation checks, and automated email alerts to create a reliable Oracle database auto-start framework. The approach is compatible with Oracle Linux 7, 8, and 9 and can be used with Oracle database versions that support the standard dbstart/dbshut utilities. It also includes a safe testing method for validating the email alert system without affecting a production database.

In this blog post, I design:

• An Oracle auto-start service using systemd
• Proper shutdown control
• An email alert system for service failures
• A safe test service to validate the alerting mechanism without production risk

This design is simple, stable, and suitable for Oracle Linux production environments.