Removed other lists (please don't cross post)
On Wed, Apr 18, 2018 at 3:47 AM, Avi Kivity <a...@scylladb.com> wrote: > Hello Cassandra developers, > > > We're starting to see client protocol limitations impact performance, and > so we'd like to evolve the protocol to remove the limitations. In order to > avoid fragmenting the driver ecosystem and reduce work duplication for > driver authors, we'd like to avoid forking the protocol. Since these issues > affect Cassandra, either now or in the future, I'd like to cooperate on > protocol development. > > > Some issues that we'd like to work on near-term are: > > > 1. Token-aware range queries > > > When the server returns a page in a range query, it will also return a > token to continue on. In case that token is on a different node, the client > selects a new coordinator based on the token. This eliminates a network hop > for range queries. > > > For the first page, the PREPARE message returns information allowing the > client to compute where the first page is held, given the query parameters. > This is just information identifying how to compute the token, given the > query parameters (non-range queries already do this). > > > https://issues.apache.org/jira/browse/CASSANDRA-14311 > > > 2. Per-request timeouts > > > Allow each request to have its own timeout. This allows the user to set > short timeouts on business-critical queries that are invalid if not served > within a short time, long timeouts for scanning or indexed queries, and > even longer timeouts for administrative tasks like TRUNCATE and DROP. > > > https://issues.apache.org/jira/browse/CASSANDRA-2848 > > > 3. Shard-aware driver > > > This admittedly is a burning issue for ScyllaDB, but not so much for > Cassandra at this time. > > > In the same way that drivers are token-aware, they can be shard-aware - > know how many shards each node has, and the sharding algorithm. They can > then open a connection per shard and send cql requests directly to the > shard that will serve them, instead of requiring cross-core communication > to happen on the server. > > > https://issues.apache.org/jira/browse/CASSANDRA-10989 > > > I see three possible modes of cooperation: > > > 1. The protocol change is developed using the Cassandra process in a JIRA > ticket, culminating in a patch to doc/native_protocol*.spec when consensus > is achieved. > > > The advantage to this mode is that Cassandra developers can verify that > the change is easily implementable; when they are ready to implement the > feature, drivers that were already adapted to support it will just work. > > > 2. The protocol change is developed outside the Cassandra process. > > > In this mode, we develop the change in a forked version of > native_protocol*.spec; Cassandra can still retroactively merge that change > when (and if) it is implemented, but the ability to influence the change > during development is reduced. > > > If we agree on this, I'd like to allocate a prefix for feature names in > the SUPPORTED message for our use. > > > 3. No cooperation. > > > This requires the least amount of effort from Cassandra developers (just > enough to reach this point in this email), but will cause duplication of > effort for driver authors who wish to support both projects, and may cause > Cassandra developers to redo work that we already did. > > > Looking forward to your views. > > > Avi > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: dev-unsubscr...@cassandra.apache.org > For additional commands, e-mail: dev-h...@cassandra.apache.org > >
