Posts Categorized: Technical Blog
Backup is one of the most important topics for any Oracle DBA. It is our primary responsibility to make sure that at any point in time we can recover database. Some time ago I created a survey,”Why do you use RMAN catalog DB for your Oracle DB backups?” In this blog post I am sharing the survey’s results.
SLOB on steroids v0.1 (you use it on your own risk). If you don’t know what is SLOB read here.
Interval partitioning – the ability to create partitions on the fly was introduced in 11g. When the feature came out, there were several nasty bugs. One such particular “limitation” has to do with parallel group by on the partition key. If you want to see just that part, skip towards the end, but I think reading the whole blog will offer some insights in how Oracle Parallel Query works.
First of all if you are using NFS to store Oracle database data files I strongly advice you to enable Oracle Direct NFS (DNFS) to access those files, the main reason is performance. DNFS removes a serialization point over the traditional “kernelized” NFS. However if you are not using NFS then most probably DNFS is out of interest for you and you should stop reading, but if you want to set it up lets go.
A while ago I was paged from a client having backup job failure. Doing my routine as usual I started the investigation by looking at the job execution log. Connected to the box and found a little bit strange output, here it is.
The most recent action I’ve done was upgrading database from 220.127.116.11 to the currently latest 18.104.22.168 version. The database is using ASM but I should notice at the beginning that the configuration is for Stand-Alone Server and not RAC. Basically when doing such action the first things that need to be done are part of the following checklist….
The traditional NoCOUG SQL challenge has been launched this year with a twist: in the wake of the “BigData” trend/buzz, it’s now been upgraded to a “SQL and/vs. NoSQL” challenge. I took on the challenge, treading through my SQL comfort zone, thinking of ways I could bend relational algebra to solve the wicked puzzle suggested this year.
We’ve got a few clients already using Enterprise Manager 12c Cloud Control. The interface and navigation have improved a lot from the 11g version in my opinion but, as with any new release of anything, there are still quite a few bugs to be fixed. Last week, after working with Oracle on some of these bugs, they asked us to apply the Bundle Patch 1 (BP1) to one of our clients’ installation. The first thing that I noticed when I started looking for information about BP1 was the amount of warnings from different people I found in MOS and around the internet.
Here is the latest MySQL news.
So how is the actual “waiting on lock” implemented? How does session B waiting for a transaction to commit started by session A, knows that the resource is free for use? To find out how it is implemented, I have traced Oracle foreground processes. I tried this on Oracle RDBMS 22.214.171.124 running on Linux. This is a excerpt of system calls being executed during a session waiting for a lock: