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From Randall Leeds <randall.le...@gmail.com>
Subject Re: memcouchd...
Date Tue, 01 Feb 2011 22:14:50 GMT
On Tue, Feb 1, 2011 at 14:01, kowsik <kowsik@gmail.com> wrote:
>> Anyway I was thinking that using your memcouchd it would be possible to
>> create an embedded couch compatible db for use in Appclerator based apps.
>> Appcelerator has partial support for commonjs and I've got your code running
>> with a few small alterations. I haven't been able to get the test suite
>> running due to issues with some of the modules from nodejs but it should be
>> doable with a bit of hacking.
>>
>> The only things missing that would make this really useful are the ability
>> to persist the documents on the device and replication. I think that the
>> documents could potentially be stored using the Properties API which stores
>> key value pairs. Unfortunately the support for manipulating binary files is
>> lacking in Appcelerator so I think implementing the couch file format would
>> be impossible without implementing it in Objective-c and Java as native
>> extensions which is possible but I'd rather avoid writing platform specific
>> code if possible.
>
> Persistence, replication and _changes are what makes Couch what it is.
> I wasn't thinking persistence at all for memcouchd, though at this
> point (for a 2 day old project), it's anybody's guess where it's going
> to go. If we can implement the _changes feed + replication without the
> persistence, I can see memcouchd being a pure transient store that can
> replicate at-will from the "real" couch.

All that is required in order to produce a semantically correct
replicator is an absolute ordering on updates like CouchDB's sequence
numbers.

>
> BTW, Just committed a partial btree implementation to memcouchd:
>
> https://github.com/pcapr/memcouchd/blob/master/lib/btree.js
>

You might have a look at nStore or node-dirty. Some work has already
gone into making these efficient.
As I recall from talking to Tim Caswell, the major limitation to
nStore at some time was file size limitations due to js not handling
big integers with 100% precision.
It may be that a database size limit is an acceptable limitation.

-Randall

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