

SQL does scale: VoltDB 0.6 scalable relational DB - wmf
http://article.gmane.org/gmane.comp.db.dbworld/23554

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codeslinger
Just as I mentioned in today's thread on FathomDB, I'd be interested in what
kind of workload scales linearly to 50 cores. I'm guessing its not very join
heavy. H-Store's main advance, IIRC, was that it pushed many points of RDBMS
engine operation into RAM. While this would indeed make the engine much faster
and eliminate some historical cruft, I don't remember any fundamental
breakthrough that would make distributed joins scale out very well. Anyone
have any insights on how they are handling joins?

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codeslinger
Some interesting points from the whitepaper regarding the above:

"VoltDB provides data access via stored procedures in order to minimize round
trips between the client and the server. Stored procedures are written in Java
- each procedure is a single Java class. Within the stored procedure
definition, users interact with a VoltDB database via an OLTP-focused subset
of standard SQL, including many-way joins, group-bys, ordering, aggregates,
common arithmetic expressions, limits, etc."

"Distributed execution planner assigns work to engines, which operate
exclusively on their assigned partitions"

I'm assuming this means they've reduced join functionality in order to get a
much better scale-out profile. I wonder what this means for people writing
apps on top of it.

