Oracle

Result cache side effects on number of calls

By Franck Pachot . During the execution of a SQL statement, you cannot guess how many times an operation, a predicate, or a function will be executed. This depends on the execution plan, on some caching at execution, and some(…)

Rolling Invalidate Window Exceeded

By Franck Pachot . Today I was doing a hard parse storm post-mortem analysis. One hypothesis was rolling invalidation causing invalidation, but figures didn't match. I often reproduce the hypothesis to check the numbers to be sure I interpret them(…)

The fastest way to get the Oracle sample schemas

Do you need the Oracle sample schemas to do a quick test or demonstration? And, as always, you did not install the sample schemas when you did the setup of your environment? The probably fastest way to get them installed(…)

Filenames in AWR reports

By Franck Pachot . If you have read my latest blog posts, you know I've measured IOPS with SLOB to estimate ACFS overhead on a fast storage. This blog is about something I learned after wasting one hour on the(…)

ODA X6 database classes and shapes

By Franck Pachot . On the Oracle Database Appliance, like on the Oracle public Cloud, you define the CPU capacity with ‘shapes’. On the latest ODA, the X6, we have a new interface to provision a database. Let’s look(…)

ODA X6 command line and Web Console

By Franck Pachot . The ODA X6 comes with a new command line (odacli) which replaces oakcli, and with a small web console which can display information about the appliance, the databases and the provisioning jobs. It also has the(…)

Unplugged pluggable databases

By Franck Pachot . When Oracle Multitenant came out in 12c, with pluggable databases, it was easy to draw them as USB sticks that you can plug and unplug to/from your Container Database (CDB). I don't like this because it(…)

Oracle serializable is not serializable

By Franck Pachot . Did you know that when you set isolation level to SERIALIZABLE, it is not serializable but SNAPSHOT? This isolation level is lower than serializable. I've never thought about it until I read Markus Winand(…)

DBA essentials workshop with release Oracle 12c is Available

It’s with pleasure to announced dbi services have upgrade the infrastructure for Oracle DBA essentials workshop. We have migrate the release of Oracle 11g R2 to the latest version Oracle 12c features and install the last PSU (April 2016).

Exadata X-5 Bare Metal vs. OVM performance

By Franck Pachot . The Exadata X5 can be installed Bare Metal or Virtualized. The latter one, Oracle VM allows to create multiple clusters on one machine, is more complex for installation and for storage capacity planning. But it allows(…)