[ZODB-Dev] transacting multiple databases

[Toby Dickenson]

On Wednesday 11 December 2002 6:35 pm, Shane Hathaway wrote:

> ... for Zope 3 we should plan to do all "mounting" using cross-database
> references.  It will be faster and more seamless.  There won't be a
> "mount point" object that conceals itself; instead, ZODB will just know
> to load the mounted object from a different database.

Is seamless a good thing? Right now I like the fact that cross-database l=
inks=20
are not handled in the lower layers (DB and down) because it means we can=
=20
have stronger invariants for those layers, such as reference checking.

In filesystem terms, today we have a crude equivalent of cross-filesystem=
=20
symbolic links.   I think there is less usefulness in something like a=20
cross-filesystem hard link (which is what I think you are suggesting), ra=
ther=20
than a better symbolic link.

> OTOH AdaptableStorage provides a very different way to mount data from
> multiple sources, and it already works with the current ZODB code.  I'l=
l
> explain how this works soon.

I am looking forward to it.