Thanks to Andy Colvin (@acolvin) and the Enkitec lab I have been able to get my hands on an ODA X4-2. And since that’s a lot quieter than turning on my own lab server, and also a lot faster I used the environment to test RAC One Node in 220.127.116.11.1. I recently had a question from a customer about the usefulness of the solution and what it brings to the HA (more...)
It seems that I’m getting more and more drawn into the world of performance analysis, and since I sometimes tend to forget things I need to write them down. I almost enjoy the “getting there” more than ultimately solving the problem. You pick up quite a few things on the way.
This environment is Exadata 18.104.22.168.1/Oracle 22.214.171.124 but as with so many things the fact that the database (more...)
One of the many interesting things I heard at the conference this time around was that Oracle’s future direction includes the use of database files on ACFS. When ACFS came out this was strictly ruled out, but has been possible for a little while now, I believe with 126.96.36.199.0. With the Oracle Database Appliance (ODA) using this deployment option and hearing about it at the conference, a little further investigation was (more...)
This is a little note, primarily to myself I guess, about the creation of the order entry schema (part of Swingbench, written by Dominic Giles) when no VNC sessions are available (although you can almost always use port-forwarding :). Instead, you can create the schema on the command line. I always execute commands on remote systems in screen for increased peace of mind. Should the network drop, the order entry generation will continue as if (more...)
Prompted by an actual task at hand I spent some time investigating an 188.8.131.52 feature – concurrent statistics gathering. It has been on my to-do list for quite some time but so far I didn’t have a use case, and use cases make it so much easier. The question was-how can I gather statistics on a really large, partitioned table? Previously, you could revert to the degree in dbms_stats.gather_table_stats to ensure that (more...)
If you ever wanted to know how Clusterware works with registered database resources, read on! It takes a little while to get your head around the concepts of the ORACLE_SID, the instance_name and the database name as well. And how Clusterware deals with all of them. Although this post has been written on 184.108.40.206.0 on Linux, it should be applicable to 11.2 Clusterware as well. Oh and by Clusterware I (more...)
My lab server has 2 SSDs, one is connected using SATA 2 and another is connected using SATA 3. I’d expect the SATA 3 connected device to be equally well equipped or even better to do work than the “old” interface. I ran SLOB on these devices to find out if there was a difference. To my great surprise the SATA2 – connected SSD performed a lot better than the SATA 3 device, as shown (more...)
During one of the classes I taught about Exadata optimisations I had an interesting question:
If I am using VPD, will Exadata still offload the query?
Background is that we discussed function offloading, and the meta-view v$sqlfn_metadata. It turned out that SYS_CONTEXT() is not offloadable in 220.127.116.11.
SQL> select name,datatype,analytic,aggregate,offloadable,descr 2 from v$sqlfn_metadata where name = 'SYS_CONTEXT'; NAME DATATYPE ANA AGG OFF DESCR -------------------------------------------------- -------- --- --- --- ------------------------------ SYS_CONTEXT UNKNOWN NO (more...)
This is yet another one of these posts that hopefully help you as much as they are going to help me in the future. Recently I enjoyed troubleshooting a problem related to parallel execution. Since I have never really written down how to tackle such a problem I thought it might be nice to do that now.
This is 18.104.22.168.0 on Exadata, but the platform doesn’t really matter for the troubleshooting (more...)
Some of you might have followed the discussion around the number of standby redo logs on twitter, but since 140 characters are woefully short for the complete story here’s the writeup that prompted the question. This is a test with 22.214.171.124 on virtualised Linux, repeated on a proper platform with physical hardware.
First of all here’s my setup. I have a dbca-based database (CDB, but doesn’t matter) that features 3 groups for (more...)