Oracle VM Consulting
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New ASM power levels in and beyond

I recently saw the following command in a script that was to be run and thought an error had been made and the power level should have been 5 not 500.


Upon doing some research it was not a mistype but a new method of disk balancing which came in from

Previously setting the power limit from 0 to 11 basically caused an additional number of ARBx process to be created to match the power level and these were removed once the rebalance had finished.

Stopping one ASM listener in Flex ASM environment takes down ASM instance

Stopping one ASM listener in Flex ASM environment takes down ASM instance

My bizarre question of 2015 already

To be honest it was asked 2 years ago in a blog about ASM and rebalancing and someone asked the following question

Using grant connect through to manage database links

Nobody can say that I am not current and topical with my posts. This post refers to functionality that was introduced in 9i, however I have just come across it and thought it useful enough to blog about it.

The command ALTER USER USERB GRANT CONNECT THROUGH USERA allows a proxy connection to be made using the username and password of USERA but  to connect in as USERB. The purpose is so that management of a user can be done without knowing that users password or changing it. This is most commonly going to be used by support teams.

I will give an example

Controlling RMAN channels on RAC

This was sent to me for posting  by my friend and ex-colleague Vitaly Kaminsky ….

I have recently worked with the customer where standard RMAN backups of production 2-node cluster ( were getting too big and taking longer than 24 hours to run.

The problem with this particular cluster was the fact that ALLOCATION of RMAN connections to the instances of the cluster was controlled by SCAN and driven by the load-balancing algorithm of SCAN.

Loading timestamp with timezone into a table using SQL Developer

I will start this post off stating  that I know there are better and more efficient methods of doing this but this is the best method I could come up with.

I had a csv file with a number of columns, one of which was data in a timestamp with timezone format.

A few rows looked like this – note I have stripped the other columns out for ease of display.

DeviceId    Timestamp
7941    11/9/2014 12:46:49 AM +00:00
8533    11/9/2014 12:46:49 PM +00:00
3692    11/9/2014 1:10:36 PM +00:00

Progress update on my AWR repository

I received an email from a team member yesterday

Have you seen this?

Interesting idea – ever thought of implementing it?

Well of course I have implemented a AWR data repository and I thought I would catch-up on where I am with it and how it is being used.

How does statistic gathering fit in with ITIL Change Management processes

In the (good) old days there was only one optimizer and plans were developed based on the precedence of the rules. For some reason I have always thought there were 11 rules but looking at the manual it tells me there are 15 rules

My misunderstandings regarding when indexes would not be used

It is normal for bloggers including myself to post about the great things they have done  – however in this case I am blogging about why I was surprised that adding a specific index had the substantial benefits it did have.

The table contains around 32M rows, is not partitioned and is on Linux

Preventing standby databases opening in Active DataGuard mode + chopt !!!

It is long been a concern of mine that it is relatively easy to open a standby database  inadvertently and then be potentially liable to a licensing cost as usage is shown in the DBA_FEATURE_USAGE_STATISTICS view.

In fact we logged an SR on the subject based on experiences on failing over using DataGuard Broker

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