Magma read performance
facundov79 at gmail.com
Thu Nov 25 12:56:55 UTC 2010
what kind of application is that? At work I'm working on a ten years old
production system with Oracle DBMS and it's 1 GB of size.
Thanks for share your analysis again,
On Wed, Nov 24, 2010 at 2:38 PM, Chris Muller <ma.chris.m at gmail.com> wrote:
> There has been interest in Magma's read and query performance lately,
> so I thought I would share results of a recent benchmark test.
> It's an actual application which does very heavy reading and writing
> to a Magma repository. This test was 24GB of repository work, over
> two days. My goal was to determine, once the persistent model becomes
> many times the size of RAM and HD access appeared to become the
> limiting factor:
> - how fast is Magma, in terms of "objects per second" and in
> "kilobytes per second"?
> - how fast is this relative to the speed when the repository was empty?
> - Magma started at 4K objects per second (empty repository), 282K per
> - Finished with 2.3K objects per second (6GB repository), 750K per second.
> - Memory consumption by the image never exceeded 300MB.
> It is important to note, these times are from the client MagmaSession
> point-of-view, including the full server roundtrip plus
> materialization. Also, as can be seen from the attached data, there
> were many requests which only brought back one or two objects which,
> while dramatically lowering the overall reported throughput, is
> actually a real-world scenario for applications.
> Verbose description:
> When the test first started the repository was tiny, and there were
> only ~4K server requests during a 5-minute monitored period. The
> total number of objects read across all ~4K requests was ~17M for an
> average throughput of 4K objects per second (ops). As the model grew
> in size and complexity, more and more objects during the 5-minute
> monitored intervals were required to perform application-posting of
> the same number of input records; doubling to ~8K server requests
> during a 5-minute period, however only a few more objects brought back
> (total 21M), for an average of 2500 ops. 32 hours after that, the
> rate of reads dropped to about 2300 ops. This is due to two factors:
> - the objects were larger (e.g., more pointers to other objects)
> - they were less clustered (having been replaced with objects which
> could not be co-located with the original object)
> The fact that objects got bigger (e.g., more pointers to other
> objects) is corroborated by another stat, "the number of *bytes* per
> second" read off the HD in order to access those objects. Initially,
> when the test first started, there were about 4K *requests* for
> objects in one of the first five-minute periods, which were read at a
> rate of 282K per second. 24 hours later, there were only 2 times as
> many requests for objects, but were read-and-materialized at a rate of
> 750K bytes / second.
> - Chris
> Magma mailing list
> Magma at lists.squeakfoundation.org
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