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September 2013

Cloud Control 12c Database Backup Jobs (Continued)

I’ve been rather critical of the way Cloud Control handles database backup jobs, as can be seen in these two previous posts.

Yesterday I found out I schedule database backups in Cloud Control the “wrong way”…

So typically, when I am sorting out a new database, I do something like this:

LAOTN Tour 2003 Interview Videos

During the OTN tour of Latin America, Pablo Ciccarello filmed a number of interviews with the speakers and has recently posted links to them here.

Right at the bottom on the page there is a link to an interview with Dana Singleterry and myself.

If you are interested in listening to our opinions of the tour, drop by and check them out.

Cheers

Tim…

System Statistics – “Exadata” Mode

Here’s a very quick note on a relatively recent addition to System Statistics. It’s the so called “Exadata mode”. This mode is intended to give the optimizer a little more info about the storage system on the Exadata platform. Here’s some info from an MOS note.

——————————————————————————————
Oracle Sun Database Machine Setup/Configuration Best Practices [ID 1274318.1]

Verify Exadata specific optimizer statistics have been gathered

 
Benefit / Impact

Quiz Night

Here’s a little quiz about Bloom filtering. There seem to be at least three different classes of query where Bloom filters can come into play – all involving hash joins: partition elimination, aggregate reduction on non-mergeable aggregate views, and parallelism.

This quiz is about parallel queries – and all you have to do is work out how many Bloom filters were used in the following two execution plans (produced by 11.2.0.2), and where they were used.

I’ve got 4 tables, 3 very small dimensions and one large fact. I’ve joined the three dimensions to the fact on their primary key, and filtered on each dimension. Stripping out the eighteen hints that I inserted to get the plans I wanted the queries both looked like this:

Best Oracle Performance Tools


 

What tools do you use? What are your favorites and why? As someone who has been working  Oracle performance tools for the last 15 years, I’m always interested in what the best tools are.

For the past 4 blog posts I’ve reviewed some tools I like such as Method-R tools, Confio, Lab128 and EMlite.

There are other tools that I especially like and are totally free such as Tanel Poder’s Moats and snapper which are two important tools for a DBA to know about.

Here is my list of tools that I’m aware of (what other tools are out there?)

 

EMlight


 

EMlight might not be as important now with Oracle 12c coming out and with Oracle’s EM Express, but EMlight is still pretty cool.  I  tried it about year  ago, and was impressed.  EMlight  is a light weight  re-write of Enterprise Manager that is dependable and improved. How is it improved? Let’s look at my favorite part, the “Top Activity” screen. The “Top Activity” screen has added a section on I/O latencies which is sorely missing from OEM’s performance page and Top Activity page. The OEM light version also includes  a list of the top events (as I did in DB Optimizer).  Very cool.

How is EMlight more dependable? With EMlight you just connect to the database and voila it works. It doesn’t require any of the brittle configuration files that OEM depends on nor the agents and processes that OEM depends on.

WordPress 3.6.1 Released…

WordPress 3.6.1 was released yesterday. You can see the list of changes here.

The auto-update feature ran though really quickly, with no problems.

Happy upgrading. :)

Cheers

Tim…

12c Indexing Extended Data Types Part I (A Big Hurt)

The maximum size for VARCHAR2, NVARCHAR and RAW columns has been extended to 32767 bytes with the Oracle 12c Database. However, indexing such columns with standard indexes comes with some challenges. These extended data types are not enabled by default within the database but can easily be done so by following these steps: Restart the […]

Advanced Oracle Troubleshooting Guide – Part 11: Complex Wait Chain Signature Analysis with ash_wait_chains.sql

Here’s a treat for the hard-core Oracle performance geeks out there – I’m releasing a cool, but still experimental script for ASH (or poor-man’s ASH)-based wait event analysis, which should add a whole new dimension into ASH based performance analysis. It doesn’t replace any of the existing ASH analysis techniques, but should bring the relationships between Oracle sessions in complex wait chains out to bright daylight much easier than before.

You all are familiar with the AWR/Statspack timed event summary below:

Advanced Oracle Troubleshooting Guide – Part 11: Complex Wait Chain Signature Analysis with ash_wait_chains.sql

Here’s a treat for the hard-core Oracle performance geeks out there – I’m releasing a cool, but still experimental script for ASH (or poor-man’s ASH)-based wait event analysis, which should add a whole new dimension into ASH based performance analysis. It doesn’t replace any of the existing ASH analysis techniques, but should bring the relationships between Oracle sessions in complex wait chains out to bright daylight much easier than before.

You all are familiar with the AWR/Statspack timed event summary below: