Re: [geogig-dev] mapdb storage module prototype

[Jody Garnett <jgarnett@xxxxxxxxxxxxxxxx>]

Very impressive work, I am not sure how "beta" mapdb is but great to have a pure java alternative. 

I thinks Gabriel is looking at sqlite still but I am not sure how it is going. 



> On Sep 11, 2015, at 10:01 PM, <Schmidt.Sebastian2@xxxxxx> <Schmidt.Sebastian2@xxxxxx> wrote:
> 
> Hi all,
> 
> during the last days, I've been experimenting with mapdb (www.mapdb.org) 
> in order to find out if it would be suitable as a backend for geogig. So 
> I prototyped a mapdb storage plugin for geogig both for objects and graph 
> databases.
> 
> https://github.com/sebastian-r-schmidt/geogig/tree/mapdb-storage
> 
> On Linux Systems I am able to do import, log, status, branch, merge and 
> show commands from the commandline. But don't expect it to be production 
> ready, it's more a functional prototype and would need a bit of 
> polishing before using it in a production context. For example, on a 
> Windows machines I ran into some weird problem with background writing 
> processes and file deletion coming from mapdb storage system. I will 
> look into that further.
> 
> If you would like to try it out have a look at
> https://github.com/sebastian-r-schmidt/geogig/tree/mapdb-storage/src/storage/mapdb 
> how to activate, current status and todos.
> 
> My Experiences with mapdb:
> * Very easy to use interface
> * Performance "feels" ok, but I didn't stress test it really yet.
> * Currently Beta releases of 2.0 are happening about every four weeks. 
> There are quite a few issues reported on the issue tracker, the author 
> seems to work on them. I'm not so sure how to judge on that - no issues 
> could also mean that no-one is using it.
> * I ran into a problem with multi key Maps and "submapping" (fixed in 
> current Snapshot Release).
> * No so sure if "beta" means Feature Completeness in the case of mapdb. 
> From 2.0-beta5 to 2.0-beta6 the internal storage format changed. Well, 
> that's we're currently doing with geogig as well, so I should not 
> complain :-)
> * Single Process Database. If one Process (or Thread) is accessing it, 
> others cannot reopen. I ran into this while trying to access a geogig 
> repo with the geoserver-geogig extension. The Code for UI integration 
> opens the DB to check which branches exist, and then it holds the 
> lock to the DB preventing the data store to be created.
> 
> Comments or even help on coding would be warmly welcomed.
> 
> Kind regards,
> Sebastian
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