Re: [boost] [persistent] Persistent library preview

Subject: Re: [boost] [persistent] Persistent library preview
From: Stefan Strasser (strasser_at_[hidden])
Date: 2010-01-10 11:30:49

Am Sunday 10 January 2010 17:03:56 schrieb Matthias Troyer:

> >>> is then fed to another program which modifies it and stores back
> >>> results. 1. Is it possible to to make boost.persistent write its data
> >>> to an HDF5 file?
> >>
> >> although theoretically possible (see "Extending Boost.Persistent") I
> >> don't think I would advise to do so. that'd be like you decided you
> >> wanted to use MySQL to process some data, but instead of exporting the
> >> data when you're done you decide to write a MySQL storage backend that
> >> can write to your file
> >> format.
> >
> > Ok. I won't go down this path then :)
>
> I actually would have exactly the same need, so maybe we can discuss
> whether this might not be still be feasible, once the library is finished.

the library already supports that, I just thought it didn't make sense to do 
it in this case.
the file format used by the backend must be able to store some internal 
information though, like e.g. the transaction ID of the transaction that made 
the last change to an object.

have a look at the concepts here:
https://svn.boost.org/svn/boost/sandbox/persistent/libs/persistent/doc/html/persistent/extending.html
especially AtomicStorageEngine or StorageEngine, depending on what kind of 
transaction guarantees your backend can give, and let me know if these 
concepts are sufficient to support your storage backend.

they are obviously the results of implementing my storage backend, so even 
though I tried to make them as generic as possible there might be some 
shortcomings.