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Oracle Team

LOB : « enq : HW contention » 

By | Hardware & Storage | No Comments

Aprés le post sur « Utilisons les securefile », revenons sur le sujet LOB avec une approche performance, stockage.

 Nous rencontrons parfois des modèles de données étranges, nous aurions envies en tant que DBA de tout reprendre à zéro pour refaire un modele relationnel en 3em forme normal (3NF), plus efficace et mieux conçu dans notre « RDBMS » favori, mais la réalité étant ce qu’elle est nous devons faire avec et au mieux.

De plus Oracle n’est pas qu’une base de données relationnelle 🙂 on l’oublie trop souvent.

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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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Stéphane Haby

Diving into Databases

By | Database Administration & Monitoring | 3 Comments

By dbi services, we are a few poeples passionate by diving.
We take this opportunity to let you dive into the two databases lakes Oracle and SQL server and see their similarities and differences. For this first level of diving (named ODD), we will not going too deep and not have narcosis or

databases toxicity.
As always, we’ll start with a short briefing to present the environment and the different themes.
Have a nice dive !

 

“BRIEFIIING !”

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Pierre Sicot

Inside Grid Control

By | Database management | No Comments

Lors de mon activité de consultant, et suite à un bug qui n’affiche pas correctement le nombre de CPU (OMS 10.2.0.5, agent 10.2.0.5 et linux x86_64), je me suis intéressé à la manière dont Oracle Enterprise Manager Grid Control (OEM GC) récupérait les informations de mémoire et de cpu sur les différents hôtes surveillés par ce dernier.

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Hervé Schweitzer

RMAN backup is failing due to “corrupt blocks”

By | Hardware & Storage | No Comments

Last week, I was not able to complete a backup because of the ORA-19566 error: “exceeded limit of 0 corrupt blocks”. Here is what you can do to fix it. Starting Point: backup error Here is the starting point of this case. The following error is found in the RMAN Backup log file: allocated channel: ch1 channel ch1: sid=25 devtype=DISK Starting backup at 27-APR-11 channel ch1: starting incremental level 0 datafile backupset channel ch1: specifying…

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David Hueber

Oracle Basics (3) – Database startup and shutdown

By | Database management | 6 Comments

It’s already quite a while that I posted my last article on the Oracle basis, so I decided to take some times in the train to continue this small serie.
This time, I’m going to speak about one of the root of Oracle administration, starting and shutting down a database.

Startup and shutdown processes within oracle databases are splitted in different steps (for startup) and modes (for shutdown) and even if these principles are quite trivial, some confusions between these steps and/or modes can easily be done. So I’m going to give a picture of both of these processes and their variations.

Before shutting any database down, it needs first to be started, so let’s begin with the startup process…

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Stéphane Haby

A brief PowerShell 2.0 overview

By | Database management | No Comments

SQL server 2008 has PowerShell and at the end of this article, I speak of this topic but to use correctly Powershell, you must have a basic notion about this technologie.

In microsoft Techdays in Basel, Marc van Orsouw presents Powershell.
I think it was a nice opportunity to presents you an overview of Powershell based on this

presentation with adding microsoft msdn web site commentar.

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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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Pierre Sicot

Pourquoi mettre une base de données Oracle en force logging ?

By | Database management | One Comment

Certaines requêtes DDL offrent la possibilité de ne pas générer des enregistrements dans les redo log via la clause NOLOGGING. Le mode nologging permet donc dans certains cas d’accélérer des traitements, ceux-ci pouvant facilement être récupérables à travers des mécanismes externes à la base de données. Ce mode peut cependant avoir des conséquences fâcheuses comme nous allons le constater et ce pas uniquement dans le contexte de configurations comme Oracle DataGuard.

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