Databases at CERN blog

CHEP 2015 papers on replication and scale-out databases

CHEP 2015, the 21st international conference on computing in high energy physics, has taken place in April 2015 in Okinawa, Japan. Here below you can find the links to the pdf of the talks, posters and related preprints of two of the contributions by members the CERN database group. These are on the topics of our tests with scale-out databases (in particular on the Hadoop platform) and on the evolution of the replication technologies used for our Oracle databases (our use of Streams, GoldenGate and Active Data Guard):

Nuances of Oracle Managed Files (OMF) and RMAN

Oracle Managed Files (OMF) have many advantages, but the fact that such files could coexist in the same database with manually added (and named) ones, could sometimes lead to confusion. Situation is made worse by the fact, that there is no straightforward way (at least of which I'm aware of...or rather was - please check the comment of Mikhail Velikikh) to say if the file is Oracle managed or not. Oracle documentation seems to confirm this:

Potential of "import catalog" command

Since version 11.1 of Oracle database, there is very useful command available, allowing DBAs to easily move RMAN recovery catalog schemas between databases. Its functionality is even broader, as it also allows one catalog schema to be merged into another - either the whole schema or just the metadata of chosen databases. Command I'm writing about is of course import catalog, which I had a chance to use recently, to move our recovery catalog to the new database.

Latest updates to PerfSheet4, a tool for Oracle AWR data mining and visualization

Topic: This post is about the latest updates to PerfSheet4 v3.7 (February 2015). PerfSheet4 is a tool aimed at DBAs and Oracle performance analysts. It provides a simplified interface to extract and visualize AWR time series data using Excel pivot charts.

 

Datafile without backups - how to restore?

Have you ever had a problem with restoring datafiles without any backups available? It's easy, of course if you have all archived logs from the time datafile was created. Please check it here: Re-Creating Data Files When Backups Are Unavailable. Moreover, RMAN is clever enough to create empty datafile automatically during restore phase and then recover it using archived logs. So far, so good, but...

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