He, Emmanuel,

thanks a lot :) That's what I wanted to know!

Referring to the MySQL docs you were pointing me to: The way I
understood MySQL partitioning, there is *no* support for vertical
partitioning.

Did I get you or the docs wrong?

And: I was supposing that you would need distributed joins with
Sequoia even now. In case one table is in DB1 and another in DB2 and
you want both in a query. Isn't that so?

And: Don't you need an SQL parser in any case? How do you find out
which tables are involved in a query without one?

Cheers

Oliver

2007/3/22, Emmanuel Cecchet <[EMAIL PROTECTED]>:
Hi Oliver,

> However, what I was interested in was:
>
> Can I have a *fragment* of a table in DB1 and another in DB2? And: The
> full table in DB3?
Partitioning a table among multiple nodes is not supported. You would
need a full SQL parser to be able to route the query to the right node
if the query could be satisfied by a single node. If the query needs
fragments from multiple nodes to be satisfied, then you need to
implement a distributed join which might be tricky especially if you
have some aggregate functions.
Updates might be even harder is it's not a single row update. An update
involving a distributed join in the where clause will be even more
complex to implement.
You also need to find a way to define how you want data to be
partitioned. You could use something like MySQL 5.1 partitioning
(http://dev.mysql.com/doc/refman/5.1/en/partitioning.html) and plug
Sequoia on top just for replication between partitions.
> Is that possible? If not (and I guess so) what might be reasonble
> extension points to Sequoia?
Nothing is impossible but it might require significant effort according
to the type of queries you want to issue to query and update the
fragmented data.

Hope this helps,
Emmanuel

--
Emmanuel Cecchet
Chief Scientific Officer, Continuent

Blog: http://emanux.blogspot.com/
Open source: http://www.continuent.org
Corporate: http://www.continuent.com
Skype: emmanuel_cecchet
Cell: +33 687 342 685


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