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May 2016

A cool thing with EXCHANGE PARTITION (part 2)

In the previous post, I showed that even though a partition was “removed” (ie, exchanged out) from a table, a query running against the table could still successfully run the completion.

However, of course, if once that partition is exchanged out, it is now a table in it’s own right…and is subject to the whims of what a DBA may wish to do with it.   If that table is dropped, or truncated, then as you might expect, our query is going to struggle to find that data ! Smile

Here’s an example of what happens when the query cannot successfully run:

Engineered Systems Healthchecks Plug-in (ORAchk)

In Enterprise Manager Cloud Control 12c release 12.1.0.3, we released the Oracle Engineered System Healthchecks plug-in which processed the XML output from the EXAchk tool, included as part of Oracle Enterprise Manager system monitoring. The EXAchk tool provides functionality for system administrators to automate the assessment of Engineered Systems for known configuration problems and best practices.

Over the years since that first release, we increased the scope and functionality of the tool, to the stage where it now has its own documention guide, Enterprise Manager ORAchk Healthchecks Plug-in User’s Guide. Notice there’s no mention of the word “EXAchk” in that title. That’s because the plug-in has been expanded so far it now includes two health check tools:

Changes to Configuration Management in EM13c

Change is difficult for technical folks.  Our world is always moving at blinding speed, so if you start changing things that we don’t think need to be changed, even if you improve upon them, we’re not always appreciative.

The best Oracle Database idea since 1992: Putting the C into ACID (We need your vote)

Oracle Rdb (only available for the VMS platform) supports SQL-92 assertions (http://community.hpe.com/hpeb/attachments/hpeb/itrc-149/22979/1/15667.doc) so why not Oracle Database? Let’s put the “C” into “ACID.”(read more)

Another reason why you should use the Data Guard Broker for your #Oracle Standby

The Data Guard Broker is recommended for various reasons, this one is less obvious: It prevents a Split-Brain problem that may otherwise occur in certain situations. Let me show you:

Experimenting with the ZFSSA’s snapshot capability using the simulator

Recently I have been asked how the Copy-on-Write cloning works on the ZFS Storage Appliance. More specifically, the question was about the “master” copy: did it have to be static or could it be rolled forward? What better than a test to work out how it works. Unfortunately I don’t have an actual system available to me at home so I had to revert to the simulator, hoping that it represents the real appliance accurately.

Setup

First I downloaded the ZFS Storage Appliance Simulator from the Oracle website and created a nice, new, shiny storage system (albeit virtual). Furthermore I have an Oracle Linux 7 system with UEK3 that will attach to the ZFSSA using dNFS. The appliance has an IP address of 192.168.56.101 while the Linux system is accessible via 192.168.56.20. This is of course a virtual toy environment, a real life setup would be quite different using IPMP and multiple paths preferably over Infiniband.

Configuration

Configuration Management Searches in EM13c

With the addition of the Configuration Management from OpsCenter to Enterprise Manager 13c, there are some additional features to ease the management of changes and drift in Enterprise Manager, but I’m going to take these posts in baby steps, as the feature can be a little daunting.

Gluent New World #03: Real Time Stream Processing in Modern Enterprises with Gwen Shapira

Update: Added links to video recording and slides below.

It’s time to announce the 3rd episode of Gluent New World webinar series! This time Gwen Shapira will talk about Kafka as a key data infrastructure component of a modern enterprise. And I will ask questions from an old database guy’s viewpoint :)

Apache Kafka and Real Time Stream Processing

Video recording & slides:

Hotsos 2016 Recap

I wanted to go to Hotsos Symposium for quite some time, having heard so many great topics from there for years. And every time I was a bit lazy to think about what I can talk about. Apparently I thought that everything I know is well covered elsewhere, so why would I be accepted. Plus all these complexities of budget, getting a visa, travel arrangements, jet lag, and personal matters in between. Last year, when call for papers was still open, I realized that there’s a good chance I can make it to Hotsos in 2016: I had a budget, visa is a doable thing, and most importantly I knew I had a topic to talk about which most likely will not be in competition with other speakers.

Cursor_Sharing problem

Here’s a possible bug (though maybe “not a bug”) that came up over the weekend on the OTN database forum. An application generating lots of “literal string” SQL was tested with cursor_sharing set to force. This successfully forced the use of bind variable substitution, but a particular type of simple insert statement started generating very large numbers of child cursors – introducing a lot of mutex waits and library cache contention. Here’s a (substituted) statement that was offered as an example of the problem: