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November 2013

The cost of Oracle

It’s not uncommon for people on one hand to expound the functionality, performance and features of Oracle, whilst on the other hand, lament the potential high cost of the product.

I’m not pontificating here – I’m commonly one of these people.  So much good stuff in Oracle….yet so much to pay to get that good stuff :-(

So in the interests of fairness, I thought I’d share a little story where an Oracle solution was implemented with total expenditure of: ZERO

VirtualBox 4.3.4

Oracle VirtualBox 4.3.4 has been released. The downloads and changelog are in the usual places. I thought 4.3.4 included a fix for the Mac OS X upgrade issue I posted about, but it didn’t. The install of 4.3.4 was seamless and didn’t require any fiddling about. :)

Hard Drive Predictive Failures on Exadata

This post also applies to non-Exadata systems as hard drives work the same way in other storage arrays too – just the commands you would use for extracting the disk-level metrics would be different.

I just noticed that one of our Exadatas had a disk put into “predictive failure” mode and thought to show how to measure why the disk is in that mode (as opposed to just replacing it without really understanding the issue ;-)

Jean Claude Van Damme : Volvo

One of my friends posted me a link to this great video.

I’m a big Jean Claude Van Damme fan and have been since I first saw him in No Retreat, No Surrender. I was at a mates house and I didn’t have access to a couple of Volvo trucks, so I had to use a couch for my response.

splits

 

Interesting Plan

A recent question on the OTN database forum included an execution plan that prompted one reader to ask: “but where has the existence subquery gone?” Here’s the original question showing the query, and here’s the later response showing the plan that prompted the question.

There were three possible reasons why that question may have been posed:

Database Articles - Johnny-G Incorporated

Going mad with subqueries? Need to get creative with SQL*Loader? Check out
my articles on these and other relational database topics.

When do Oracle Parallel Execution Slaves issue buffered physical reads – Part 2?

In the previous post about in-memory parallel execution I described in which cases the in-mem PX can kick in for your parallel queries.

A few years ago (around Oracle 11.2.0.2 and Exadata X2 release time) I was helping a customer with their migration to Exadata X2. Many of the queries ran way slower on Exadata compared to their old HP Superdome. The Exadata system was configured according to the Oracle’s “best practices”, that included setting the parallel_degree_policy = AUTO.

Replicating Tanel’s Script Library

Tanel does offer a zip file with all of his scripts. The zip seems up-to-date now; I started doing this alternative technique awhile ago when the zip file didn’t seem to get updated as quickly as the raw scripts directory.

  mkdir tpt
  cd tpt

wget -r -nH --cut-dirs=2 --no-parent --reject="index.html*" http://blog.tanelpoder.com/files/scripts/

  cd ..

[svn/git] add tpt
[svn/git] commit tpt -m "added Tanel Poder's script library to our script repository"

Please remember that as Tanel says on his own website, “always proofread the scripts and test their effect out in a test environment before running in production.”

Replicating Tanel’s Script Library

Tanel does offer a zip file with all of his scripts. The zip seems up-to-date now; I started doing this alternative technique awhile ago when the zip file didn’t seem to get updated as quickly as the raw scripts directory.

  mkdir tpt
  cd tpt

wget -r -nH --cut-dirs=2 --no-parent --reject="index.html*" http://blog.tanelpoder.com/files/scripts/

  cd ..

[svn/git] add tpt
[svn/git] commit tpt -m "added Tanel Poder's script library to our script repository"

Please remember that as Tanel says on his own website, “always proofread the scripts and test their effect out in a test environment before running in production.”

When do Oracle Parallel Execution Slaves issue buffered physical reads – Part 1?

This post applies both to non-Exadata and Exadata systems.