[elephant-devel] gp-export

[Ian Eslick]

gp-export sounds very useful.  I actually implemented something  
similar to help convert databases from one lisp to another (string  
serialization is not compatible across lisp implementations).  This  
would be a more general solution to my hack.  I'll look at it when I  
get a chance.

Cheers,
Ian

On Apr 24, 2009, at 1:04 PM, Alex Mizrahi wrote:

> helo
>
> (Short introduction for those who does not know what is this about:
> gp-export is a tool
> to export/import databases in human-readable (SEXP) format, with
> serialization based on
> s-serialization of cl-prevalence, meant to work with different  
> databases. In
> previous discussions
> it was considered as a path of migration between version 0.9 and 1.0  
> of
> elephant/postmodern.)
>
> Just a few monthes passed, and I've made gp-export that is suitable  
> for
> migration from 0.9 to 1.0. :)
> The problem was that there was no support for btrees whatsoever, so  
> I had to
> refactor it badly.
> Anyway, now it seems to work and it even has some tests.
>
> However, for now gp-export does not back up whole store -- it only  
> iterates
> through all objects
> it finds in index and dumps them together with all their slots etc.  
> It is
> such because it was meant
> to be working with various stores. (But it supports only elephant/ 
> postmodern
> so far.)
> But probably if we also backup store root as some fake object  
> instance, it
> would make full
> elephant store backup.
>
> Also, there are some backend-specific pieces in exporter, such as  
> what slots
> to filter out.
> I've only made support for postmodern, if one wants it to work with  
> BDB, he
> needs to add support.
> Also, migration is backend-specific (as it needs to map between btree
> classes), maybe it needs
> some refactoring to be unified.
>
> So, the questions are:
>   Is there a need for such thing?
>   Are backups described above full/good enough?
>   Should it be somehow bundled with elephant or maintained separately?
>   Are there people who'd like to hack it to add support for different
> stuff?
>   (Well, I can do this, but I'm not very fast :) )
>
> By the way, besides gp-export, I've considered using elephant's  
> migration
> for 0.9 to 1.0 upgrade:
>
> postmodern-0.9 --migration--> bdb-0.9 --upgrade--> bdb-1.0 -- 
> migration-->
> postmodern-1.0
>
> However, migration does not work right in version 0.9... And I'm not  
> very
> enthusiastic about
> digging old code. I've asked about this some time ago, as nobody  
> replied I'm
> assuming nobody
> cares, so I'm officially giving up.
>
> with best regards, Alex 'killerstorm' Mizrahi.
>
>
>
>
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