Many people have asked me this question that how they can learn Exadata ? It starts sounding even more difficult as a lot of people don’t have access to Exadata environments. So thought about writing a small post on the same.
It actually is not as difficult as it sounds. There are a lot of really good resources available from where you can learn about Exadata architecture and the things that work differently from any non-Exadata (more...)
I was troubleshooting some Windows hangs on my Desktop system running Windows 8 and enabled driver verifier. Today when I tried to start VirtualBox it failed with this error message.
Failed to load VMMR0.r0 (VERR_LDR_MISMATCH_NATIVE)
Most of the online forums were asking to reinstall VirtualBox to fix the issue. But one of the thread mentioned that it was being caused by Windows Driver Verifier. I disabled it, restarted Windows and VirtualBox worked like a (more...)
Few months ago I contributed a chapter (on Monitoring, Troubleshooting and Performance tuning) to a GoldenGate book on Oracle Press that Robert Freeman was authoring. Thought of posting a small update that the book is now out. My name doesn’t appear on the main page but you will see it (more...)
So there is a new toy in the market for database geeks : Oracle has released database 12c. Every social platform is abuzz with the 12c activity. So thought that I should also complete the ritual
In this post Aman has already summed up many important links.
Maria Colgan has (more...)
Yesterday I was configuring EM 12c for a Sun Super Cluster system. There were a total of 4 LDOMs where I needed to deploy the agent (Setup –> Add targets –> Add targets manually). Out of these 4 everything went fine for 2 LDOMs but for the other two it (more...)
Just a quick note about change in the way the compute nodes are patched starting from version 18.104.22.168.1. For earlier versions Oracle provided the minimal pack for patching the compute nodes. Starting with version 22.214.171.124.1 Oracle has discontinued the minimal pack and the updates to compute nodes are done via Unbreakable Linux Network (ULN).
Now there are three ways to update the compute nodes:
1) You have internet access on the Compute nodes. In this case you can download patch 13741363, complete the one time setup and start the update.
There was an interesting issue at one of the customer sites. Few tables in the database were altered and the dependent objects became invalid. But the attempts to compile the objects using utlrp.sql or manually were failing. In all the cases it was giving the same error:
SQL> alter function SCOTT.SOME_FUNCTION compile;
alter function SCOTT.SOME_FUNCTION compile
ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-01422: exact fetch returns more than requested number of rows
ORA-06512: at line 27
At first look it sounded like some issue with the dictionary as (more...)
Sometimes you may need to run GoldenGate on some different machine than the one that hosts the database. It is very much possible but some kind of restrictions apply. First is that the Endian order of both the systems should be same and the second is the bit width has to be same. For example it is not possible to run GoldenGate on a 32 bit system to read from a database that runs on some 64 bit platform. Assuming that the environemnt satisfies the above two conditions; we can use the LOGSOURCE option of TRANSLOGOPTIONS to achieve this.
Here we (more...)
Just a quick note/post about the significance of COMPRESS and TCPBUFSIZE parameter in performance of a GoldenGate Extract Pump process. COMPRESS helps in compressing the outgoing blocks hence helping in better utilization of the bandwidth from source to target. GG is going to uncompress the blocks before writing them to the remote trail file on the target. Compression ratios of 4:1 or better can be achieved. Of course, use of COMPRESS may result in increased CPU usage on both the sides.
TCPBUFSIZE controls the size of the TCP buffer socket that is going to be used by the Extract. If the bandwidth allows, it (more...)
Hybrid Columnar Compression (HCC) is a new awesome feature in Exadata that helps in saving a lot of storage space in your environment. This whitepaper on Oracle website explains this feature in detail. Also Uwe Hesse has an excellent how to use all this post on his blog. You can see the compression levels one can achive by making use of HCC. It is very simple to use feature but one needs to be aware of few things before using HCC extensively as otherwise all your storage calculations may go weird. Here are few of the things to keep in (more...)