Archive for the 'Oracle ORION' Category

A Tip About the ORION I/O Generator Tool

I was recently having a chat with a friend about the Oracle ORION test tool. I like Orion and think it is a helpful tool. However, there is one aspect of Orion I thought I’d blog about because I find a lot of folks don’t know this bit about Orion’s I/O profile.

Generating an OLTP I/O Profile With Orion
If you use Orion to simulate OLTP, be aware that the profile is not exactly like Oracle. Orion uses libaio asynchronous I/O routines (e.g., io_submit(2)/io_getevents(2)) for reads as well as writes.This differs from a real Oracle database workload, because the main reads performed by the server in an OLTP workload are db file sequential reads which are random single-block synchronous reads. For that matter, foreground direct path reads are mostly (if not entirely) blocking single block requests. The net effect of this difference is that Orion can generate a tremendous amount of I/O traffic without the process scheduling overhead Oracle causes with blocking reads.

There is a paper that includes information about ORION in the whitepapers section of my blog. Also, ORION is downloadable from Oracle’s OTN website.

Trivial Pursuit
Why is it that random single-block synchronous reads are called db file sequential read in Oracle? Because the calls are made sequentially, one after the other. It is not because the target disk blocks are sequential in the file being accessed.


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I work for Amazon Web Services. The opinions I share in this blog are my own. I'm *not* communicating as a spokesperson for Amazon. In other words, I work at Amazon, but this is my own opinion.

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All content is © Kevin Closson and "Kevin Closson's Blog: Platforms, Databases, and Storage", 2006-2015. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Kevin Closson and Kevin Closson's Blog: Platforms, Databases, and Storage with appropriate and specific direction to the original content.

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