oracle performance

kevinclosson's picture

Whitepaper: Oracle Database 11g and 12c Consolidation and Workload Scalability with EMC XtremIO 3.0

This is a just a quick blog post to direct readers to the best Oracle-related paper detailing the value EMC XtremIO brings to Oracle Database use cases.  I’ve been looking forward to the availability of this paper for quite some time as I supported (minimally, really) the EMC Global Solutions Engineering group in this effort. They really did a great job with this testing! I highly recommend this paper for readers who are interested in:

rshamsud's picture

Demos do fail.

I am an ardent believer of “show me how it works” principle and usually, I have demos in my presentation. So, I was presenting “Tools for advanced debugging in Solaris and Linux” with demos in IOUG Collaborate 2015 in Las Vegas on April 13 and my souped-up laptop (with 32G of memory, SSD drives, and an high end video processor etc ) was not responding when I tried to access folder to open my presentation files.

Sometimes, demos do fail. At least, I managed to complete the demos with zero slides </p />
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arupnanda's picture

Cache Buffer Chains Demystified

You must have seen sessions waiting on the event “latch: cache buffers chains” from time to time. If you ever wondered what this means and how you can reduce time spent on it, read on.

arupnanda's picture

OOW14 Session: SQL Tuning Without Trying

Many thanks to all those who attended my session "SQL Tuning without Trying" at Oracle Open World 2014 #oow14. I hope you found the session useful.

If you want to download the slide deck, here it is. As always, I would really, really like to hear from you.

kevinclosson's picture

SLOB Physical I/O Randomness. How Random Is Random? Random!

I recently read a blog post by Kyle Hailey regarding some lack of randomness he detected in the Orion I/O generator tool. Feel free to read Kyle’s post but in short he used dtrace to detect Orion was obliterating a very dense subset of the 96GB file Orion was accessing.

rshamsud's picture

Visualizing AWR data using python

In my earlier post, I talked about, how tableau can be used to visualize the data. In some cases, I find it useful to query AWR base tables directly using Python and graph it using matplotlib package quickly. Since python is preinstalled in almost all computers, I think, this method will be useful for almost everyone. Of course, you may not have all necessary packages installed in your computer, you can install the packages using install python packages . Of course, if you improve the script, please send it to me, I will share it in this blog entry.

Script is available as a zip file:


rshamsud's picture

inmemory area is another sub-heap of the top-level SGA heap

I blogged earlier about heap dump shared pool heap duration and was curious to see how the inmemory – new feature – is implemented. This is a short blog entry to discuss the inmemory area heap.


I have set the initialization parameters sga_target=32G and inmemory_size=16G, meaning, out of 32GB SGA, 16GB will be allocated to inmemory area and the remaining 16GB will be allocated to the traditional areas such as buffer_cache, shared_pool etc. I was expecting v$sgastat view to show the memory allocated for inmemory area, unfortunately, there are no rows marked for inmemory area (Command “show sga” shows the inmemory area though). However, dumping heapdump at level 2 shows that the inmemory area is defined as a sub-heap of the top level SGA heap. Following are the commands to take an heap dump.

kevinclosson's picture

EMC XtremIO – The Full-Featured All-Flash Array. Interested In Oracle Performance? See The Whitepaper.

NOTE: There’s a link to the full article at the end of this post.

I recently submitted a manuscript to the EMC XtremIO Business Unit covering some compelling lab results from testing I concluded earlier this year. I hope you’ll find the paper interesting.

There is a link to the full paper at the bottom of this block post. I’ve pasted the executive summary here:

rshamsud's picture

Data visualization, px qref waits, and a kernel bug!

Data visualization is a useful method to identify performance patterns. In most cases, I pull custom performance metrics from AWR repository and use tableau to visualize the data. Of course, you can do the visualization using excel spreadsheet too.

Problem definition
We had huge amount of PX qref waits in a database:

KarenMorton's picture

Upcoming Webinar: Writing SQL Right on May 20

Coming up on May 20, I'll be delivering a webinar entitled Oracle SQL Performance: Writing SQL Right. Registration is now open. Once again the webinar will be hosted by Embarcadero and there will be two sessions - one at 10am ET and one at 2pm ET.


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