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August 2014

ASH presentations from John Beresniewicz

 

John Beresniewicz and I worked hand in hand on developing the performance pages in Oracle Enterprise Manager. John is one of the foremost experts on active session history (ASH) queries and he has recently posted some of his presentations on ASH to slideshare:

 

Renaming an Oracle Apache Target in EM12c

When installing Enterprise Manager 12c, the host value can come from a number of places for different applications/tiers.  For most, it comes from the environment variable $ORACLE_HOSTNAME, (for Windows Servers, %ORACLE_HOSTNAME%).

Dealing with Wi-Fi Problems the DBA Kevlar Way

As much as KSCOPE 14 fixed any and all Low-T levels, it couldn’t do anything for our the WiFi problems we were experiencing back in May. I’ve been a telecommuter for almost 4 straight years now and was quite frustrated when our WiFi service became dismal back then.

To Hint or not to hint (Application Engine), that is the question

Over the years Oracle has provided a number of plan stability technologies to control how SQL statements are executed.  At the risk of over simplification, Outlines (deprecated in 11g), Profiles, Baselines and Patches work by injecting a set of hints into a SQL statement at parse time.  There is quite a lot of advice from Oracle to use these technologies to fix errant execution plans rather than hint the application.  I think it is generally good advice, however, there are times when this approach does not work well with PeopleSoft, and that is due to the behaviour and structure of PeopleSoft rather than the Oracle database.

To Hint or not to hint (Application Engine), that is the question

Over the years Oracle has provided a number of plan stability technologies to control how SQL statements are executed.  At the risk of over simplification, Outlines (deprecated in 11g), Profiles, Baselines and Patches work by injecting a set of hints into a SQL statement at parse time.  There is quite a lot of advice from Oracle to use these technologies to fix errant execution plans rather than hint the application.  I think it is generally good advice, however, there are times when this approach does not work well with PeopleSoft, and that is due to the behaviour and structure of PeopleSoft rather than the Oracle database.

The Expendables 3

It’s a holiday weekend and I just got back from watching The Expendables 3.

OK. You don’t go to a film like this expecting an Oscar winning script, but come on! During the end credits, when it said “Story by Sylvester Stallone”, I thought of a scene from Boogie Nights where they discus the plot of an adult movie about 30 seconds before they start to shoot, which goes something like this…

“Enter Reed to audition for Amber. They go at it.

Dirk enters. Meets with Becky. They go at it.”

In the case of The Expendables 3, the same sort of thing must have happened, but something like this…

Don’t go directly to Maximum Protection!

With a Data Guard Configuration in Maximum Performance protection mode, don’t go to Maximum Protection directly, because that leads to a restart of the primary database:

 Attention!

ALS Ice Bucket Challenge : Keeping It In The Family

If you watched my (No) Ice Bucket Challenge yesterday, you will know I nominated my Oracle family.

The first family member to step up to the plate was the daughter, Heli “Hell-Squirrel” Helskyaho. She shared the video on Facebook, which you can see here if you are a friend. We have to be careful with the parental controls to keep her safe!

Next up was the wife, Debra Lilley, who used the opportunity to do an Oscar acceptance speech.

In-memory Aggregation

The title of this piece is the name given to a new feature in 12.1.0.2, and since I’ve recently blogged about a limitation of the in-memory option I thought I’d pick this feature as the next obvious thing to blog about. This is a bit of a non sequitur, though, as the feature seems to have nothing whatsoever to do with the in-memory option; instead it’s a cunning mechanism combining aspects of the star-transformation (but without the bitmap indexes), Bloom filters, and “group-by” placement to minimise the cost of aggregation over high-volume joins.

Here’s a small data set I’ll use to demonstrate the feature:

AWR Warehouse

I just noticed last week that there is a new patch for Enterprise Manager and it is enabling AWR Warehouse feature. There is a note ID 1901202.1 which describe bundle patch for OEM 12c release 4.

Today I had a chance to install it in my lab and now I can start testing new OEM feature.
There is some documentation here and on Kellyn's blog.