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In most applications, the performance of the persistence layer is very unlikely to be a bottleneck.
More likely the design of the datastore itself, and in particular its indices are more likely to
have the most impact, or alternatively network latency. That said, it is the DataNucleus projects'
committed aim to provide the best performance possible, though we also want to provide functionality,
so there is a compromise with respect to resource.
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What is a benchmark?
This is simply a series of persistence operations performing particular things
e.g persist
n
objects, or retrieve
n
objects. If those operations are
representative of your application then the benchmark is valid to you.
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To find (or create) a benchmark appropriate to your project you need to determine the
typical persistence operations that your application will perform. Are you interested in
persisting 100 objects at once, or 1 million, for example? Then when you have
a benchmark appropriate for that operation, compare the persistence solutions.
For performance of DataNucleus Access Platform, please refer to the
Performance Tuning Guide
Please refer to the following
blog entry
for our take on performance of DataNucleus.
The PolePosition benchmark is a project on SourceForge
to provide a benchmark of the write, read and delete of different data structures using the
various persistence tools on the market. JPOX was run against this benchmark just before
being renamed as DataNucleus and the results are found
in the DataNucleus Wiki.
The input data used for that benchmark run is found
in JPOX SVN.
Some comments on the PolePos benchmark :-
-
It is essential that tests for such as Hibernate and DataNucleus performance comparable
things. Some of the original tests had the "delete" simply doing a "DELETE FROM TBL" for Hibernate
yet doing an Extent followed by delete each object individually for a JDO implementation. This is
an unfair comparison and in the source tree in JPOX SVN this is corrected. This fix was pointed
out to the PolePos SourceForge project but is not, as yet, fixed
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It is essential that schema is generated before the test, otherwise the test is no longer
a benchmark of just a persistence operation. The source tree in JPOX SVN assumes the schema
exists. This fix was pointed out to the PolePos SourceForge project but is not, as yet, fixed
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Each persistence implementation should have its own tuning options, and be able to add
things like discriminators since that is what would happen in a real application. The source
tree in JPOX SVN does this for JPOX running. Similarly a JDO implementation would tune the
fetch groups being used - this is not present in the SourceForge project but is in JPOX SVN.
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DataNucleus performance is considered to be significantly improved over JPOX particularly
due to batched inserts, and due to a rewritten query implementation that does enhanced fetching.
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