Just thought I'd mention that trunk now has support for non memory
mapped buffers. When starting Neo4j just pass in:


as a parameter to the public EmbeddedNeo( String storeDir,
Map<String,String> params ) constructor.

The code of plain buffer/direct buffer ports of previously memory
mapped ones are:


On Tue, May 5, 2009 at 8:22 PM, Johan Svensson <> wrote:
> Next release of Neo4j (b9) will have an option not to use memory
> mapped buffers but instead either use direct buffers or normal Java
> buffers. A .NET port could replace the
> with a different
> implementation that does not use the MappedByteBuffer (b9 will soon
> have such an implementation).
> In the transaction package any usage of MappedByteBuffer can be
> replaced with a direct or normal buffer also (they all just append
> data to some file).
> Hopefully I will get my test code of the new persistence windows into
> trunk soon. Once that is done a .NET port could make use of that and
> replace all other usages of memory mapped I/O with normal buffers.
> Regards,
> Johan
> On Sun, May 3, 2009 at 10:03 PM, Antonello Provenzano
> <> wrote:
>> I dug a bit the NIO package and the use done in neo4j: unfortunately
>> there's not counter part for it on .NET nor the possibility to
>> recreate [easily] classes to support it. In fact, you make a wide and
>> important use of MappedByteBuffer on files: although implement the
>> logics of a ByteBuffer class is not difficult (in .NET schema is the
>> association of two classes: MemoryStream and
>> BinaryWriter/BinaryReader), the behavior of MappedByteBuffer appears
>> to be more complex, since access to portion of data in file which
>> access must be coordinated with the memory, and this is not a simple
>> issue.
>> As of Java implementation, this is done natively and it's a complex
>> operation to replicate the same functionality.
>> Once this is solved, I see no further [major] obstacles to the port:
>> avoiding the integration with the System.Transactions mechanism, the
>> base of neo4j port would work in its core functionalities.
>> Cheers.
>> Antonello
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