Reply to post: Re: Relational?

Yugabyte's double-decker DBaaS follows Cochroach in distributed RDBMS

W.S.Gosset Silver badge

Re: Relational?

Thanks for that. Sorry, it was late and I was just bimbling on my phone with my brain at half-mast. Now it's early and I'm nursing a coffee.

You pointed me at https://docs.yugabyte.com/latest/architecture/transactions/isolation-levels/ .

So, sadly, it appears it does NOT do full serialisation. No predicate locking, only locking of existing data. That is, it can not protect against changes in scope intra-transaction. Or rather: increases in scope -- decreases will be blocked. So: not SQL-92 compliant. (Very few "r"dbms's are) Oh well.

Of graver concern is the implication that the isolation management is not handled by the engine. It's handled by the interface layers. Note the distinction between the YSQL and YCQL APIs. Different codebases replicating the same functionality ... there's a maintenance nightmare waiting to happen. I remember Sybase ran that route for speed, different tweaked codebases for different query plans, and some were buggy: you could alter say the order of your tablelist and trigger a Cartesian product. Eurgh. I banned Sybase in our Sydney office when I discovered that.

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