Hmm. Okay. I open a transaction for three days (let's say indefinitely), maybe reading a few tuples here and there and updating a few, but never committing. How does this system not fall over? I guess it could abort my transaction...
Still, I think their performance numbers can be legit, because they are much, much slower than what a handful (much less than 24) machines could do if fully partitioned and without coordination. 500KRead/Second on such small values is not really fantastic performance over 24 machines. I also don't understand the initial burst-capacity on the read-side either, although I can guess -- on writes it can make sense because some work is deferred, but I'm trying to understand how that can happen on reads as well. My guess is a transaction ID allocation on-read that hits a wall somewhere.
Another common use case is I want to take a consistent backup/copy. For large databases, this is a very, very long snapshot to maintain, if MVCC, or a lot of locks to acquire, if 2PL. How does the system act then?
All in all, I think it's pretty neat, and I like that someone is dealing with OLTP database problems with a mind towards easing one's burden via transactions.
Still, I think their performance numbers can be legit, because they are much, much slower than what a handful (much less than 24) machines could do if fully partitioned and without coordination. 500KRead/Second on such small values is not really fantastic performance over 24 machines. I also don't understand the initial burst-capacity on the read-side either, although I can guess -- on writes it can make sense because some work is deferred, but I'm trying to understand how that can happen on reads as well. My guess is a transaction ID allocation on-read that hits a wall somewhere.
Another common use case is I want to take a consistent backup/copy. For large databases, this is a very, very long snapshot to maintain, if MVCC, or a lot of locks to acquire, if 2PL. How does the system act then?
All in all, I think it's pretty neat, and I like that someone is dealing with OLTP database problems with a mind towards easing one's burden via transactions.