bdarnell
Joined 16 years ago
Joined 16 years ago
Google Reader's
built with electrons and leptons, meters and liters.
We're off dealing with those particles
so we can bring you your articles.Cockroach Labs is not your only option; you can also use other providers that have a license agreement with us. Our first partner in this area is ObjectRocket: https://www.objectrocket.com/blog/cockroachdb/introducing_co...
The details are in the "additional usage grant" clause: https://github.com/cockroachdb/cockroach/blob/8acfe8ffd0028c...
We decided to draw the line at whether the end user has direct control over table schemas. If users can specify the schema to be used, it's a database service and needs a license. If you're fitting everything into a generic schema (even if the user can specify things that look like new columns in the UI), it's an application and doesn't need a special license.
For comparison, in CockroachDB (disclosure: I'm a co-founder of Cockroach Labs), we don't have any features that let you execute server programs, but we do have something analogous to `pg_{read,write}_server_files` via the BACKUP, RESTORE, and IMPORT commands. In order to use these commands with a target on the server's filesystem, though, the database `admin` role isn't enough. The server also needs to be started with the `--external-io-dir` flag (and file operations will be limited to that directory). This gives an extra layer of opt-in before filesystem operations are allowed.
How exactly does the "free checking" example work?
Is it two transactions, where each transaction is responsible for checking the total balance across all accounts? Or is it three transactions, where a third read-only transaction verifies the sum of all accounts?
If it's two transactions, I think the anomaly as described is prevented even by non-strict serializability, because the additional reads force the transactions to conflict. If it's three transactions, then what we're really concerned with is the read-only transaction. What does it mean to mix some strictly-serializable transactions and non-strictly-serializable ones?