I guess everybody who is working with Oracle databases and has been involved with Oracle Exadata in any way knows about smartscans. It is the smartscan who makes the magic happen of full segment scans with sometimes enormously reduced scan times. The Oracle database does smartscans which something that is referred to as ‘offloading’. This is all general known information.
But how does that work? I assume more people are like me, and are anxious (more...)
I have also spent time working with MySQL a relational database with open source roots, now part of Oracle. In this post I want to talk about my impressions of MySQL and some tips and tricks I learned working with it.
First and for all, you will have to be ready (more...)
This notes are really just a reminder to myself of the typical "issues" that I encounter every time I do a new install of OEL 6.x and 126.96.36.199These notes are in addition to the excellent installation instructions given by oracle-base.com: oel install, DB 11.2.0.x install
The notes listed below are just a reminder to myself of things that I seem to always have to look (more...)
It describes how to create an xml document as an XMLType with an Oracle SQL Query.
The query that is described is based on a pretty simple table, with no relationships. I'm creating a new course based on a datamodel we created years ago, that contains data. I wanted to abstract some of that data (more...)
See http://www.oracle.com/technetwork/developer-tools/sql-developer/downloads/sqldev-releasenotes-v4-1925251.html for the details.
But I’m not going to talk about performance.
This article is some kind of warning.
First I’ll show you how result cache works on a normal view.
I’ll create a table, a view on this table and a function that (more...)
Just a quick note to highlight that the Oracle pre-built Developer VMs have been updated for Oracle 12c.
Oracle has released the much-anticipated version of cellsrv compatible with Oracle Database 188.8.131.52 (patch #16980054). Before thinking about upgrading, read MOS note #1571789.1 carefully. Unless you are planning to run database 12c on your Exadata, it would be advisable to continue down the 11.2 branch (more...)
Today, Oracle announced the Exadata X4-2 model. The X4 has some considerable improvements, namely:
This is the fourth of twelve articles in a series called Operationally Scalable Practices. The first article gives an introduction and the second article contains a general overview. In short, this series suggests a comprehensive and cogent blueprint to best position organizations and DBAs for growth.
This article – building (more...)
SQL performance can degrade for many reasons, some of most common are:
- plan changes
- data skewness
- low caching efficiency
- data growth
All these factors are relatively well known. A somewhat less common, although not exceptionally rare scenario, is read consistency overhead due to concurrent (more...)
I heard a strange report from a client late last week - they weren't getting any smart scans on their Exadata - a data warehouse, no less (and we checked to see if cell_offload_processing was set to true). Queries would run normally, but for some reason, the "cell physical IO (more...)