Striving for Optimal Performance
  • ⌂
  • Blog
    • Archive
    • Categories
    • Search
  • Troubleshooting Oracle Performance
    • Description
    • Structure
    • Table of Contents
    • Forewords
    • Reviews
    • Downloadable Files
    • Addenda and Errata
    • First Edition
  • Publications
  • Public Appearances
    • Past Public Appearances
  • Contact
  • About

The APPROX_MEDIAN Function – A Test Case

30 October 2017 Written by Christian Antognini

The aim of this post is not to explain how the APPROX_MEDIAN function works (you find basic information in the documentation) but to show you the results of a test case I ran to assess how well it works. Here’s what I did… I started in the Oracle Database Public Cloud an instance of version […]

Read More Leave a Comment

Approximate Aggregate Transformation (AAT)

2 November 2016 Written by Christian Antognini

There are situations where approximate results are superior than exact results. Typically, this is the case when two conditions are met. First, when the time and/or resources needed to produce exact results are much higher than for approximate results. Second, when approximate results are good enough. Approximate results are for example superior in case of […]

Read More Leave a Comment

Adaptive Query Optimization Configuration: Parameters, Preferences and Fix Controls

7 October 2016 Written by Christian Antognini

The aim of this post is to summarize the knowledge about the 12.1 and 12.2 adaptive query optimizer configuration that, as far as I know, is spread over a number of (too many) different sources. First of all, let’s shortly review which adaptive query optimization features exist: Adaptive plans, which are only available in Enterprise […]

Read More 9 Comments

SQL Trace in Oracle Database Exadata Express Cloud Service

25 September 2016 Written by Christian Antognini

Today I started having a look to the Oracle Database Exadata Express Cloud Service announced last week at Oracle OpenWorld. Note that since the amount of resources provided (in summary, 1 OCPU, 20 or 50 GB of database storage) is very limited, in general, in my opinion that service will only be useful for functional […]

Read More 3 Comments