13. 01. 2020.

Descending Index type – performance and limitations

The main topic of this article is the DESC index type, which is often mixed-up with the Btree index type because of the great similarity they share when looking at the index creation syntax. “Raison d’etre” for having DESC index type is to avoid expensive sorting when you are sure you’ll always query and sort […]

07. 01. 2020.

Oracle database links – performance impact

In this post I’m going to explain the most important drawbacks when using db links technology for purposes for which it is not design for. To be more precise, the case in which db links are used to massively exchange data between many separate databases will be explained. In the previous post you can find […]

02. 01. 2020.

Oracle database links – locking strategy

In this post mechanism of Oracle database link technology along with locking strategy used by Oracle database will be described. Today in almost all production environments based on Oracle databases where I’ve been called to help with optimization & tuning, it is a quite common to have at least one or more db links to […]

16. 12. 2019.

Oracle RAC in the AWS Cloud – performance testing part III

This is the last part of the series called “Oracle RAC in the AWS Cloud”. In my previous article I’ve promised to put a Oracle RAC cluster under the crazy load. It was time to fulfill my promise. My previous articles you can find on the following two links: https://www.performatune.com/en/oracle-rac-in-the-aws-cloud-performance-testing-part-i/ & https://www.performatune.com/en/oracle-rac-in-the-aws-cloud-performance-testing-part-ii/ Let’s go straight […]

09. 12. 2019.

Oracle RAC in the AWS Cloud – performance testing part II

In the 2nd part of the Oracle RAC in the AWS Cloud series I’ll present test results of Oracle 2 nodes RAC databases running on AWS public cloud based on Flashgrid’s Skycluster deployment. You can take a look at my previous article that are related to how to deploy & setup environment for Oracle RAC […]

03. 12. 2019.

Oracle RAC in the AWS Cloud – performance testing part I

Last time, all components (network, storage, Grid infrastructure…) are prepared for Oracle database RAC installation with a minimal time and effort thanks to Flashgrid’s wizard which, behind the scene, is using Cloud Formation template to setup everything, including installation of all necessary patches available at the time of installation.   You can find more on […]

05. 09. 2019.

Reducing CPU consumption and Oracle licenses by fixing context switching in Oracle Db

Context switching is one of the most overlooked topics when tuning the Oracle database, as you can’t simply see it directly (e.g. “context switching” wait event doesn’t exist). Instead you should use indirect approach (through the increased CPU consumption), as it’s recorded as a CPU wait event. Context switching what it is and what impact […]

23. 08. 2019.

Oracle single-threaded CPU performance reference test, native compilation and performance improvement after upgrading your database

In this article I’ll provide a very simple way of how to test Oracle CPU single-thread performance.   Apart from that, I’ll cover performance boost you might expect when upgrading your server (especially CPU), expected performance boost when performing simple upgrade of the Oracle database, and issues and workarounds related to native compilation of PL/SQL […]

28. 07. 2019.

How to quickly perform REST API performance test

REST API interface is dominant way of machine-to machine communication because of its flexibility, performance, simplicity and lightweight.   Recently I had to perform a quick performance test to check if response time of one application is in line with SLA (Service Level Agreement). Such performance tests are particularly important in case of SaaS architecture […]

22. 07. 2019.

Oracle database benchmarking by using CALIBRATE_IO

CALIBRATE_IO is yet another popular database simulation/stress test utility, mainly used to perform IO benchmarks.   Procedure, that is part of DBMS_RESOURCE_MANAGER package, will generate read-only workload made up of 1 MB of random of I/Os to the database to determine the maximum number of IOPS and MB per second. You can save the following […]