Oracle ASM 12c: New Features

Last week I was lucky enough to be presenting at the UKOUG AIM SIG. There was a decent enough crowd in attendance and there were some really interesting talks and some really good speakers. In particularly I found Chris Lawless speaking on replication a particularly engaging speaker, and Dave Webster really held the audiences attention late in day.

I was giving a presentation on the new features available to you with 12c ASM. The presentation (more...)

Thoughts on UKOUG tech 13

So the annual UKOUG technology conference has come and gone for yet another year. This time it was in a new location, having moved away from its regular berth in Birmingham. Manchester is not a city I’m that familiar with, the only previous time I had been there was a (more...)

VritualBox 4.30 on OS X 10.9 Mavericks

I’ve been using OS X for a very long time, and one of the Applications that is invaluable in my day to day work is VirtualBox. It’s a great application allowing you to work with various Oracle versions and products, and I have quite a few linux VMs with differing (more...)

OpenWorld 2013

I’ve just come back from my 5th trip to Oracle OpenWorld. While there is something very special about your first trip to OpenWorld, this has been my favourite trip of the lot. In previous years I’ve blogged about what’s been going on every day, but for me, twitter and @jarneil (more...)

Cloning Oracle 12c Pluggable Databases

The wait is over and Oracle 12c has finally arrived. Of course there is a lot of interesting and useful looking new features, but one of the eye-catchers is the major architectural shift to multi-tenancy with the Container Database and Pluggable Database features.

To actually create a container database with (more...)

Recovering from rm -rf on a datafile

This blog posting is entirely the credit of Frits Hoogland, who pointed out to me that this was possible.

I managed to delete a datafile, that while it had been created in a completely stupid location, was very much in use. I’m sure we’ve all been there, I mean (more...)

Online patching: The Good, the Bad, and the Ugly

I’ve worked on 24×7 systems for more than a decade, and I have a real dislike of downtime. For one, it can be a real pain to agree any downtime with the business, and while RAC can and does help when you do work in a rolling fashion, there is still risk.

The promise of online patching has been a long one, and it is only recently that I dipped my toe in the water with them. Unfortunately, they are not a panacea, and in this blog posting I’m going to share some of the downsides.

Of course not all (more...)

Observing Exadata HCC compression changes when adding columns

This blog posting is very much a follow on from the previous entry on how data compressed with Exadata HCC compression behaves under changing table definitions. Many thanks to Greg Rahn for the comments on the previous blog entry on a simple mechanism for determining whether the compression level has changed or not.

In this blog posting we add a column to an HCC compressed table and we observe whether the number of blocks in the table changes or not.

As Greg stated in the comments on the previous blog entry, we have 3 possibilities for adding a column:

  1. add (more...)

Adding Columns and Exadata HCC compression

While everyone is aware of the issues of mixing EHCC compression and OLTP type activities, I had a customer who was interested in finding out what happens upon adding a column to a table that has EHCC compression enabled on it.

As I could not see any definitive statements in the documentation on this particular scenario I ran up some tests to see the behaviour.

First of all they are using partitioning by date range, so we create a partitioned table:

SQL: db01> create table t_part  ( 
username varchar2(30), 
user_id  number, 
created date ) 
partition by range (created) 
( partition  (more...)

Creating ASM diskgroups on Exadata with ASMCA

I recently had the chance to create some diskgroups on an Exadata box outside the standard installation procedure, while this is not necessarily Exadata specific, I thought the technique of using ASMCA silently on the command line to create the diskgroups was sufficiently novel for a short blog posting. If for nothing else but to remind myself on how to do this in future.

This example uses the disks presented from a quarter rack exadata system and creates a diskgroup called DATA01:

asmca -silent -createDiskGroup -diskGroupName 'DATA01' -diskList o/192.168.10.14/DATA01_CD_00_cel01,o/192.168.10.14/DATA01_CD_01_cel01,
o/192.168.10.14/DATA01_CD_02_cel01,o/192.168. (more...)