I noticed something for the first time tonight when I was playing around in the Enkitec lab – something that I have been doing wrong for a while. When working in the lab, I often rely on the crsctl command to shut down the entire cluster stack for me. It’s really easy to use “crsctl stop cluster -all” followed by “dcli -l root -g ~/dbs_group /u01/app/184.108.40.206/grid/bin/crsctl stop crs” to get everything down (more...)
We had a client that was running into a strange issue on their Exadata where new connections coming in through the SCAN were failing. After doing some troubleshooting, it was discovered that it was related to one of the SCAN listeners not properly accepting requests from new sessions. The VIP and listener were running, and everything looked normal.
We had the following SCAN setup:
|SCAN VIP #||VIP IP|
Special thanks to my colleague who spotted odd results which led us to this finding.
My test (virtual) environment is:
OS: Oracle Enterprise Linux 5.8
DB: Oracle EE 220.127.116.11.12
In test I (more...)
In the Oracle technical universe, it seems that the end of the calendar year is always eventful. First there’s OpenWorld: obviously significant for official announcements and insight into Oracle’s strategy. It’s also the week when many top engineers around the world meet up in San Francisco to catch up over beers – justifying hotel and flight expenses by preparing technical presentations of their most interesting and recent problems or projects. UKOUG and DOAG happen shortly (more...)
rman target /
Recovery Manager: Release 18.104.22.168.0 - Production on Wed Sep 18 20:47:38 2013
Oracle BI Publisher Desktop Microsoft Visual Basic System Error &H8000FFFF -2147418113 Catastrophic failure
Not too sure what I changed on my laptop, possibly just installation of another product or perhaps Microsoft or similar updates, but when I went to edit a BI Publisher RTF template I got the following error message on clicking ANY button in the BI Publisher plugin for Microsoft Word.
I’ve been working on a lot of good schtuff lately on the area of capacity planning. And I’ve greatly improved my time to generate workload characterization visualization and analysis using my AWR scripts which I enhanced to fit on the analytics tool that I’ve been using.. and that is Tableau.
So I’ve got a couple of performance and capacity planning use case scenarios which I will blog in parts in the next few days or weeks. But before that I need to familiarize you on how I mine this valuable AWR performance data.
Let’s get started with the AWR top (more...)
Lately I’ve been busy on projects and research so I’m putting more and more stuff on my wiki/braindump… and really I need to catch up on blogging.
I have a longer draft post about SQLTXPLAIN.. but I haven’t finished it yet so I’ll just go with the quick post for now.
I’ve been using SQLTXPLAIN for quite a while, and I can say I’m a really big fan. It’s a cool tool to use for systematic SQL Tuning so I got them all neatly documented here http://karlarao.tiddlyspot.com/#SQLTXPLAIN.
BTW, Carlos Sierra, the author of the tool will (more...)
Getting tired of typing and setting your ORACLE_HOME, ORACLE_SID and troubleshooting your . oraenv ?
going/connecting to different client sites with different platforms and server environments sometimes it is frustrating just how long it takes to get a proper SQL*Plus environment
So I always make use of this script
and for every server that I access I just have to do three bits of typing:
. ~oracle/.karlenv <<– set the environment
2 <<– choose an instance
s <<– rlwrap'd sqlplus alias
see example usage below:
[root@desktopserver ~]# su - oracle [oracle@desktopserver ~]$ [oracle@desktopserver ~]$ vi .karlenv <-- copy (more...)
One of the easiest ways to understand something is to see a visualization. Looking at Active Session History (ASH) data is no exception and I’ll dive into how to do so with R and how I used R plots to visually present a problem and confirm a hypothesis. But first some background…
Frequently DBAs use the Automatic Workload Repository (AWR) as an entry point for troubleshooting performance problems and in this case the adventure started the same way. In the AWR report Top 5 Timed Foreground Events, the log file sync event was showing up as the #3 (more...)
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I have extended the Undo usage scripts to include two additional indicators:
1) undo change vector size statistics
2) Used undo records/blocks
Then the script for Oracle 11g is as follows:
set pagesize 400 set linesize 140 col name for a25 col program for a50 col username for a12 col osuser for a12 SELECT a.inst_id, a.sid, c.username, c.osuser, c.program, b.name, a.value, d.used_urec, d.used_ublk FROM gv$sesstat a, v$statname (more...)
I often get asked to take a look at an Oracle eBusiness Suite concurrent request to see what it is doing, this can come from a few different angles:
- What requests are currently running?
- I have an operating system process that is taking too much CPU - what is it doing?
- Can you tell me where the request is at? I've clicked on the log but it doesn't show anything!
- My request is taking too long - can you check for blocking locks?
There are a number of strategies to track and trace where things are at for a running (more...)
Earlier I did a presentation at VirtaThon which is the same topic that I presented at Hotsos 2011.. Mining the AWR and Capacity Planning are very dear to my heart and up until now I’m using every research I did on that presentation to work on an “Exadata Provisioning Tool” which I’m planning to present at the next Hotsos 2012… well, the only thing that’s different this time is.. my attendees are virtual geeks all over the world
I was at the Virtual Room #100, and the staff earlier were really helpful and most of all I had fun (more...)
Dave Abercrombie mailed me earlier that the May 2011 NoCOUG Journal is already out and can be viewed online at http://www.nocoug.org/Journal/NoCOUG_Journal_201105.pdf.
I met Dave at Hotsos 2011 when he attended my presentation.. apparently we have the same interest about Statistics, Linear Regression, AWR, AAS and he’s got awesome blogs about it at http://aberdave.blogspot.com. Also being the Journal Editor at Northern California Oracle Users’s Group, he invited me to write a short article about the question:
Why is my database slow?
The NoCOUG Journal having a very wide readership with the last issue being downloaded around 6000 times from (more...)
Hotsos 2011 – Mining the AWR Repository for Capacity Planning, Visualization, and other Real World Stuff
For all that loves Oracle performance.. Hotsos is truly the best conference, all the speakers are performance geeks, all the attendees talks about performance. Everything is about performance! There are lot more stuff that I like about my first Hotsos experience, the following are some of them..
I like that presenters and attendees are curious about what each performance geek has to say..
I like that whenever their brains are already fried. They consume as much coffee/soda as they can.. and just lay their butts on this couch.. and still.. talk about performance.
I like that after all the sessions, (more...)
I just got back in the office from a 2 week conference + vacation (SFO,WAS,NY). Then I was finally back in shape to work and do the usual geek stuff again but suddenly my Neo laptop suddenly stopped working! (the one I mentioned here, but it’s now on Fedora)
It can’t even boot to BIOS, certainly a case worse than BSOD.
So after fiddling with the laptop and systematically ruling out other component failures (power cable,monitor,memory,HD), Yes it’s much like troubleshooting an Oracle database! … we decided to bring it to the service center.
But wait! it may (more...)