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From Emmanuel Lécharny <>
Subject Re: A default backend based on Google FlatBuffers?
Date Sat, 19 Sep 2015 16:40:01 GMT
Le 19/09/15 13:55, Zheng, Kai a écrit :
> Thanks Emmanuel for the feedback.
> Yeah, it needs encoding, that means the flatbuffers format should be used to store entries.
> It does avoid decoding data, because it operates directly on the binary data. In details,
one may mmap loads the content from a file and gets a bytebuffer. Then all the entries can
be looked up directly on the bytebuffer. As you said one may find an entry efficiently, I
thought a mapping from key to the start address of the corresponding object would be required.
Given the start address of the object, then all the fields of the object can be directly retrieved
without any decoding.

What I don't get is how you go from a Java instance to a flatbuffer...
Because, make no mistake, the costly processing is the serialization. In
flatbuffer, how is this serialization done ?

For instance, in ApacheDS, we serialize entries and other data using our
own implementation, not depending on any Java default serialization
(through reflection). the gain is massive. That's what I don't get :
what's the flatbuffers offer that is better than what we do when
serializing 'by hand' ?

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