Application integration & Middleware

How to retrieve previous table statistics using Oracle dbms_stats

Sometimes, you need to modify the statistics of a table. There are various reasons: either for the performance analysis or because the execution plan changed. Oracle offers two methods: statistics restore or statistics export. Both are in the dbms_stats package.

A SQL statement is slow and suddenly fast? Have a look at “Cardinality Feedback”!

Discussing with some tuning gourous we were made aware about this feature. It is not so far from the adaptive cursor sharing perfectly described in  Chris's blog : http://antognini.ch/papers/BindVariablePeeking_20090718.pdfThis feature, compares the real execution(…)

Simulating and testing I/O performances with ORION

Since Oracle 11.2, Oracle provides ORION in the RDBMS binaries (in ${ORACLE_HOME}/bin). ORION is an I/O calibration tool allowing to simulating and testing I/O performances an Oracle database would be confronted with.   ORION basically supports four kinds of database(…)

Simulating database-like I/O activity with Flexible I/O

You do not want to install or configure swingbench, load runner etc. – just to test the performance of your I/O system based on filesystems? Then Flexible I/O is the right tool for you. This post provides an overview. In(…)

Oracle 11g Instance Caging – limit database CPU consumption

As you certainly already have heard Oracle 11g came with a new feature called “Instance caging”. This feature allows Oracle DBA to easily manage Oracle Instance CPU-consumption. How does it work? Quite easily … see below(…)

Oracle index compression: eliminating duplicate column values

Index compression comes from Oracle 8i and has quite the same mechanism as table compression. Index compression eliminates duplicate column values in the leaf blocks. Let's see how it works:(…)

MySQL Workbench 5.2: changing the life of MySQL developers and DBAs

MySQL Workbench provides several necessary tools in order to manage a MySQL environment. MySQL Workbench 5.2 is available for Windows, Mac and Linux platforms, it encapsulates three main functionalities: 1.    SQL Development: Allows connecting to existing databases and run SQL(…)

How to avoid strange figures in the Oracle optimizer system statistics

Have you ever noticed strange figures while collecting the Oracle optimizer system statistics ? If so, you need to provide the optimizer with the correct number. In this posting, I will show you how.