sar -d on Linux

I started using sar -d to look at disk performance on a Linux system this week and had to look up what some of the returned numbers meant.  I’ve used sar -d on HP Unix but the format is different.

Here is an edited output from a Linux VM that we are copying files to:

$ sar -d 30 1
Linux 2.6.32-504.3.3.el6.x86_64 (myhostname)  04/01/2015      _x86_64_        (4 CPU)

05:26:55 PM        (more...)

DCLI to back up Oracle home and inventory before patch

I was preparing for my weekend patch of our Exadata system and I needed to back up all of our Oracle homes and inventories on our production system.  On our 2 node dev and qa clusters I just ran the backups by hand like this:

login as root

cd /u01/app/oracle/product/

tar -cvf - dbhome_1 | gzip > dbhome_1-20150211.tgz

cd /u01/app

cp -r oraInventory oraInventory.20150211

But the production cluster has 12 nodes (more...)

Loads of fun with DBA_HIST_OSSTAT

I saw a load of 44 on a node of our production Exadata and it worried me.  The AWR report looks like this:

Host CPU
            Load Average
 CPUs     Begin       End     %User   %System      %WIO     %Idle
----- --------- --------- --------- --------- --------- ---------
   16     10.66     44.73      68.3       4.3       0.0      26.8

So, why is the load average 44 and yet the CPU is 26% idle?

I started looking at ASH data and (more...)

Arizona Oracle User Group Meeting March 18

Sign up for the Arizona Oracle User Group (AZORA) meeting next week: signup url

The email that I received from the meeting organizer described the topic of the meeting in this way:

“…the AZORA meetup on March 18, 2015 is going to talk about how a local business decided to upgrade their Oracle Application from 11i to R12 and give you a first hand account of what went well and what didn’t go so well. ”


Delphix User Group Presentation

My Delphix user group presentation went well today. 65 people attended.  It was great to have so much participation.

Here are links to my PowerPoint slides and a recording of the WebEx:

Slides: PowerPoint

Recording: WebEx

Also, I want to thank two Delphix employees, Ann Togasaki and Matthew Yeh.  Ann did a great job of converting my text bullet points into a visually appealing PowerPoint.  She also translated my hand drawn images into useful drawings.  Matthew did an (more...)

Blog third anniversary

My first blog post was March 5, 2012, three years ago today.

I have enjoyed blogging.  Even though I am talking about topics related to my work blogging does not feel like work. The great thing about blogging is that it’s completely in my control.  I control the content and the time-table. I pay a small amount each year for hosting and for the domain name, but the entertainment value alone is worth (more...)

Joined twitter

I joined twitter.  I don’t really know how to use it.  I’m setup as Bobby Durrett, @bobbydurrettdba if that means anything to you. :)

– Bobby

Different plan_hash_value same plan

I mentioned this same effect in an earlier post about SQL profiles: link

I get a different plan_hash_value values for a query each time I run an explain plan or run the query.  I see this in queries whose plan includes a system generated temporary segment like this:

|   1 |  TEMP TABLE TRANSFORMATION   |                             |

For some reason the system generated temporary table (more...)

Speaking at Delphix User Group Webex March 11

On March 11 at 10 am California time I will be speaking in a Delphix User Group Webex session.

Here is the sign up url: WebEx sign up.

Adam Leventhal, the Delphix CTO, will also be on the call previewing the new Delphix 4.2 features.

I will describe our experience with Delphix and the lessons we have learned.  It is a technical talk so it should have enough details to have value to (more...)

A new index on a small table makes a big difference

A few weeks back on the weekend just before I went on call we got a complaint about slowness on an important set of reports.  I worried that the slowness of these reports would continue during my support week so I tried to figure out why they were slow.  I reviewed an AWR report for the 24 hours when the reports were running and found a simple query against a tiny table at (more...)