Infrastructure at your Service

 
Hervé Schweitzer

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

By | Application integration & Middleware | 2 Comments

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.pdf

This feature, compares the real execution (number of returned/actual rows “A-rows”) with some expectations (number of expected rows “E-rows”) and chooses another plan for the next executions if the difference between the expectation and the actual result is too big. “Cardinality Feedback” is not well documented in the Oracle documentation.

Read More
Grégory Steulet

Saving time and increasing service availability with MySQL Enterprise Monitor 2.3

By | Hardware & Storage | 3 Comments

Nowadays MySQL Databases are encapsulated into many mission critical software solutions. Lots of companies host one or many MySQL databases in their data center, sometimes even without knowing it except when the MySQL service is no more available. In order to increase this service availability it is mandatory to have a monitoring solution. Regardles of you are using MySQL Server, MySQL replication or cluster the Oracle/MySQL monitoring solution is called MySQL Enterprise Monitor.

Read More
Grégory Steulet

Stop looking for Oracle and MySQL documentation: use the dbi services firefox add-ons!

By | Database management | 2 Comments

Are you often trying to find some functionalities into ORACLE 10gR2, ORACLE 11gR2 or MySQL documentation ? Of course each time you are looking for this documentation you find unofficial documentation which is never corresponding to the version you are looking for.. we have the solution, three firefox add-ons that will allow you to easily find the right official Oracle or MySQL documentation you are looking for.

Read More
Grégory Steulet

Simulating and testing I/O performances with ORION

By | Application integration & Middleware | One Comment

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 activities based on either small or large I/O. ORION can, as any respectable I/O simulation tool, generate an adapted workload using a given percentage of reads and write operations.

Read More
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…

Read More
Hervé Schweitzer

How to debug a Data Pump error

By | Database management | One Comment

Recently, I had an Oracle error with Data Pump at a Customer, which was not easy to localize. Here is the error I received during a DBIOWNER schema export with Data Pump:

Processing object type SCHEMA_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
ORA-39125: Worker unexpected fatal error in KUPW$WORKER.UNLOAD_METADATA while calling DBMS_METADATA.FETCH_XML_CLOB [TABLE_STATISTICS]
ORA-00942: table or view does not exist

Read More
Grégory Steulet

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

By | Application integration & Middleware | 2 Comments

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 Queries, SQL scripts, edit data and manage database objects. This functionality replaces the ones previously provided by the Query Browser stand-alone application.

2.    Data Modeling: Helps to create and manage models, allows forward & reverse engineering and provides capability to compare and synchronize schemas

3.    Server Administration: Helps to configure a database server, to setup user accounts and browse status variables and server logs

 

Let’s have a look deeper in each of those features:

Read More
Oracle Team

SQL Developer 3.0 : prêt pour les DBA

By | Technology Survey | No Comments

La nouvelle version d’Oracle SQL Developer (version 3.0.03.45) est prête pour les administrateurs de base de données/DBA (voici une vidéo sur cette version). Elle s’est vue agrémentée d’outils nécessaires aux tâches d’administration. Les tests ci-dessous vous présentent, à travers quelques copies d’écrans, les fonctionnalités de l’outil,  en espérant vous donner l’envie de l’adopter.

Read More