Infrastructure at your Service

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Yann Neuhaus

Yann Neuhaus

Oracle space management & recycle bin

By | Database management | One Comment

This post describes some basic Oracle database management issues database administrators might be confronted with. It is about space management and differences observed while monitoring the available space from several point of views (tablespace/datafile) in Grid Control 11g. It also relates and explains an issue (ORA-01652) observed on pre 11.2 Oracle releases (targets) concerning the tablespace/datafile space management and the recycle bin. First of all, a simple example: let’s check the used and available space…

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Yann Neuhaus

How to retrieve previous table statistics using Oracle dbms_stats

By | Application integration & Middleware | 4 Comments

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. 1. Statistics restore This method uses the procedure dbms_stats.restore_%_stats, where % can be table, schema, database, and fixed_objects. This is an example for a restoration of a table with definite timestamp. The starting situation is:…

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Yann Neuhaus

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

By | Application integration & Middleware | No Comments

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 order to simulate Oracle database I/O workload on filesystems, ORION cannot be used since it only uses raw or block devices (scratching the filesystem). To simulate Oracle database I/O behaviour on filesystems, we can use…

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Yann Neuhaus

Password Oracle : vos mots de passe sont-ils sécurisés ?

By | Database management | No Comments

Quelles sont les faiblesses de l’encryption des mots de passe Oracle ? Comment est-ce qu’Oracle crée les clés de hachage afin d’en améliorer la sécurité ? C’est ce que je vous propose de découvrir dans ce post. Le mot de passe est la forme la plus commune d’authentification. Ce dernier est stocké dans une table Oracle sous la forme d’une clé de hachage. Lorsqu’un utilisateur tente de se connecter, le mot de passe saisi est…

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