Topic: This post is about investigating the Oracle Optimizer using stack sampling and flame graphs. We will see how the complexity of the Optimizer has increased over the years and in particular with the introduction of cost-based optimization and more recently with 12c adaptive optimization.
Topic: This post is a hands-on introduction to using on-CPU Flame Graphs for investigating Oracle workloads. This technique is about collecting and visualizing sampled stack trace data to analyze and troubleshoot Oracle processes at the OS level (in particular applied to Linux).
Indexes… what indexes?
Indexes are one of the key Oracle features in terms of improving query performance and one might think it should be clear to everybody when and how to use them. Not at all... Working as a DBA for several years I was surprised to notice that so many developers do not know what indexes are, how they work and how to use them efficiently. I thought it would be good to put this knowledge down in a series of blog posts… and here we are! Let’s start with…
If you plan to introduce changes in your environment and want to estimate their impact, Real Application Testing feature seems to be one of the best options. As we needed to check the influence of changes planned in our databases, I've started to look for good candidates to capture the workloads. I wanted to capture only workloads associated with small number of schemas, but from several databases, to be able to properly simulate as much types of production workloads existing in our databases as possible.
If you consider migrating to Oracle Database 12c, no matter if you think of development, testing or production environments, one of many decisions you need to take is to define what to do with the auditing.
Topic: This blog entry is about investigating Oracle's DBMS_RESOURCE_MANAGER.CALIBRATE_IO
select 'Hello World' from dual@CERN;
Welcome to this new blog: “Databases at CERN, powering particle physics”. Why yet another blog?
The goal of this blog is to make the work around databases at CERN better known by sharing technical information to a wider audience. And who knows… it might trigger your interest in joining us for an internship, a fellowship or as a staff member.