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October 2012

Oracle Database File System (DBFS) in Oracle 12c : WebDav Support?

On a yoga course a teacher said to the group, “Don’t try to remember everything I say. Some things will come back to haunt you later.”

So I was reviewing a couple of chapters of Marcelle Kratochvil‘s multimedia book and she mentioned DBFS. That jogged a memory of the DBFS demo stand at OOW12, where the guy told me that 12c will (probably) have WebDAV support for DBFS.

DBFS is a neat feature, but it’s a little frustrating if you are using any OS other than Linux because you are forced to use a client utility with limited functionality, rather than accessing it like a regular file system as you can on Linux using the FUSE project. If this WebDAV functionality does get released in 12c it will make it accessible from pretty much any OS or browser.

VirtualBox 4.2.4 Released…

VirtualBox 4.2.4 has been released. Downloads and changelog in the usual places.

I’ve literally not had chance to upgrade all by VMs with the guest additions since the update released last week. :)

Happy upgrading. :)



Running Total

Here’s a question on OTN from a  SQL Server user that should prompt a few interesting ideas. Re-arranged and paraphrased it goes something like this:

In SQL Server I can write the following code:

SELECT @Counter = 0

UPDATE TempDB.dbo.TransactionDetail
SET @Counter = AccountRunningCount = @Counter + 1
FROM TempDB.dbo.TransactionDetail WITH (TABLOCKX)

What I want to do is more like this:

DECLARE @Total INT = 0
UPDATE StringOutput
set @Total = SumOfLength = @Total + ColLength

How do I do something similar in Oracle ?

Scale Abilities Awarded Gold Partner of the Year

Scale Abilities is very proud to announce that we have secured first place (Gold) in the UKOUG Partner of the Year Awards in the Database category. Thanks go out to all our clients that voted for us, we really appreciate your support and hope that we continue to exceed your expectations moving forward. Our competitors in […]

New Version Of XPLAN_ASH Utility

A new version 2.0 of the XPLAN_ASH utility introduced here is available for download.You can download the latest version here.The change log tracks the following changes:- Access check- Conditional compilation for different database versions- Additional activity summary- Concurrent activity information (what is/was going on at the same time)- Experimental stuff: Additional I/O summary- More pretty printing- Experimental stuff: I/O added to Average Active Session Graph (renamed to Activity Timeline)- Top Execution Plan Lines and Top Activities added to Activity Timeline- Activity Timeline is now also shown for serial execution when TIMELINE option is specified- From on: We get the ACTUAL DOP from the undocumented PX_FLAGS colu

My public appearances in autumn 2012

The era of different conferences before the end of this year is here.
Last week I was speaking at Slovenian Oracle User Group Conference in Ljubljana and later on in the same week at Croatian Oracle User Group Conference in Rovinj.

Here is the list of my forthcoming public appearances:

Does the Parse Time Increase Linearly with the Number Of Child Cursors?

In the last post I discussed a test case generating lot of child cursors. Today I wanted to show you, for the very same test case, that in 11.2 the parse time might increases linearly with the number of child cursors per parent cursor. This is the expected behavior. In fact, to check whether an already available child cursor can be reused, the list of child cursors must be scanned. And, in case no one of the already available child cursors is compatible, every entry needs to be probed.

Skip Scan

A recent question on OTN asked how you could model a case where Oracle had the choice between a “perfect” index for a range scan and an index that could be used for an index skip scan and choose the latter path even though it was clearly (to the human eye) the less sensible choice. There have been a number of wierd and wonderful anomalies with the index skip scan and bad choice over the years, and this particular case is just one of many oddities I have seen in the past – so I didn’t think it would be hard to model one (in fact, I thought I already had at least two examples somewhere in my library – but I couldn’t find them).