[elephant-devel] Lisp-only data store (prototype)

John develgenius at gmail.com
Fri Feb 6 21:21:46 UTC 2009

As we're still learning Elephant, we are not currently using cursors.
However, one thing I'm thinking is that we will definitely have the
following scenario:

We define a class for storing log information, which is timestamped and we
create an index on the timestamp. The purpose for this is so that we could
"easily" get the MIN and MAX timestamp from a list of a few million objects.
Without looking at the implementation of cursors and just looking at the
documentation, I think it would be easier (and possibly more efficient) to
set a cursor on the index and get cursor-first and cursor-last, instead of
having to map-index and the entire set of millions of objects.

Would that qualify as a reasonable need of cursors?


On Thu, Feb 5, 2009 at 8:44 AM, Ian Eslick <eslick at media.mit.edu> wrote:

> Would map functions, as described by leslie, accomplish the same thing
> with a little rewrite?
> I would say that we want some way for users of a current store in
> elephant-unstable to migrate to elephant-1.0 - we do have a solid set
> of postmodern users.  I'd be surprised if anyone is still using the
> original 0.9.1 - but let's give it a few days and see if anyone shouts.
> If you like I can look at migration in 0.9.1, but it will be a little
> bit before I can get to it.
> Would it make sense to include gp-export into elephant proper or make
> it an easy option to load/use?  The online migration is a bit of a
> pain to maintain over certain changes to the way the stores work; it
> would be nice if we had a path that was less prone to error to bypass
> code for complex backwards compatibility in the future if needed.
> Ian
> On Feb 5, 2009, at 6:36 AM, Alex Mizrahi wrote:
> > IE> How many people currently directly use the Btree/cursor interface?
> >
> > we use cursors to iterate through multiple sequences in order, e.g. we
> > want, say 10 latest items that satisfy certain criteria, and
> > candidates
> > come from different indices.
> >
> >
> >
> >
> > _______________________________________________
> > elephant-devel site list
> > elephant-devel at common-lisp.net
> > http://common-lisp.net/mailman/listinfo/elephant-devel
> _______________________________________________
> elephant-devel site list
> elephant-devel at common-lisp.net
> http://common-lisp.net/mailman/listinfo/elephant-devel
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.common-lisp.net/pipermail/elephant-devel/attachments/20090206/0740ede1/attachment.html>

More information about the elephant-devel mailing list