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Multitenant internals: object links on fixed tables

By Franck Pachot . The previous post partly answered to the original question (why an object link to V$SESSION is refreshed only every 30 seconds): recursive queries on shared=object views. Now let's see what is different(…)

Multitenant internals: how object links are parsed/executed

By Franck Pachot . I had a comment on object links internals when creating a sharing=object view on GV$SESSION. Before posting about this specific case, I realized that I've never explained how a query on(…)

List usernames instead of uids with the ps command for long usernames

By William Sescu Have your ever faced such a situation. You have usernames in your /etc/passwd file with more than 8 characters. This is no problem for Linux at all, usernames may be up to 32 characters long, only your(…)

How to do a Filesystem Resize (ext3/ext4) on Redhat running on VMware

By William Sescu A filesystem resize can be done in several ways, online, offline, with LVM2 or without LVM2.  However, this blog will describe how to do an online resize of ext3/ext4 filesystems where a virtual disk (vmdk) is online(…)

SQL Server AlwaysOn: troubleshooting improvements with new service packs

As promised in my latest blog, I will talk about improvements in the detection of the availability group replication latency. As a reminder, replication latency between high(…)

Exadata X-5 Bare Metal vs. OVM load testing

By Franck Pachot . In a previous post I tried to compare a single thread workload between Exadata X5 Bare Metal and Virtualized. The conclusions were that there is no huge differences, and that this kind(…)

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).

Shrinking Oracle VM VirtualBox with Zerofree

In this blog I would like to talk about Shrinking a Virtual Machine with Oracle databases and MySQL which is install. Unfortunately, whilst Virtual Box will dynamically expand the hard drive as it’s required, it won’t dynamically shrink it(…)

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(…)