cruppstahl

Correct.

I ran sysbench benchmarks with 30 concurrent connections. The performance gap between InnoDB and upscaledb shrank a bit, but not much.

The reason is that most of the performance is spent in MySQL and not in the key/value store, and then it does not make a big difference if the key/value store is concurrent or not.

In my experience the assumption of "concurrent = fast" is a misconception. Right now upscaledb moves certain operations (i.e. flushing dirty buffers) to the background. It is better to have fast single-threaded code instead of multi-threaded code with a huge locking overhead. A compromise would be to move the lock to the database level (instead of the Environment, which is basically the container for multiple databases), and make sure that there's no shared state between the databases. But that actually does not have that much priority for me because I do not expect to win that much performance.

It's ok! The example storage engine could implement more functionality, just to demonstrate i.e. how rows are serialized/deserialized etc. The test suite was very helpful.

Not necessarily. I ran sysbench with InnoDB and manually switched off transactions, and it was a lot slower. I don't know why - didn't look into it.

upscaledb does use transactions. I.e. if you insert a row with a primary and a secondary index then upscaledb inserts two key/value pairs in two databases. All these operations are wrapped in Transactions. They are just not yet supported on SQL level.

If that's your definition of atomicity - yes, upscaledb offers atomic operations. If you define atomicity as the "A" in "ACID" then no - BEGIN/COMMIT wrappers are not yet available. Work in progress!

BEGIN/COMMIT is not yet supported. But that's on my TODO list.

Thanks for the insights!

Interesting - thanks for your answers!

Agree for a website. I'm selling software licenses, avoiding personal liability would be interesting (if it was affordable).

"Found a small company (UG) with 500EUR capital to hold rights on the site if you want to further professionalize this project."

Can you elaborate a bit? I have the same problem as the original poster. But founding a company requires IHK membership fees and tax consultant fees. From what I hear this amounts to ~ 1500 €/year.

That's interesting - are the 64bit versions available for download?