A Dissabte 13 Octubre 2007, Gokulakannan Somasundaram va escriure:
> Even otherwise we are recommending Indexes with snapshot as an option. We
> are not replacing the current index scheme. So if someone feels that his
> database should run on lesser disk space, let them create the normal index.
> If he feels he can afford to have more redundant disk space, then he can
> create indexes with snapshots. We are reducing random I/Os at the cost of
> extra disk space. So definitely that's a good. But tech folks like us can
> better decide on something based on experiments, as Tom has pointed out. So
> let's see whether Indexes with snapshot is worth the trade-off in space.
>
There's also LucidDB [1], another open souce column based data base. But if
you look at the features section in their web page, you'll see they use
page-level multi-versioning. So they are avoiding the need for storing
snapshot information for each tuple, I think that has to be kept in mind.
I'd really like that PostgreSQL could gain some features ala Column Based
databases, so the administrator could choose how he wants to use the
database, but I don't think we'll be able to compete with them if they store
snapshot informatin per page, and we're storing it per tuple, for example. So
any step in this directoy will probably mean understanding the decisions
they've made in their architectures.
[1] http://www.luciddb.org/
--
Albert Cervera i Areny
http://www.NaN-tic.com