It is common for some operations, like system table updates, to try and guarantee
some particular ordering of operations.
The way Origin does it, is by simply incrementing one to the current timestamp.
Our calls, however, are being dispatched through our internal query processor, which
has a builtin client_state.
Our client_state has a mechanism to guarantee monotonicity, by adding 1 if needed
to operations that happen subsequentially. By using a clock that is not wired up
to this mechanism, we can't really guarantee that if other operations happened to
get in between.
If we expose this mechanism through the query_processor, we will be able to guarantee
that.
Signed-off-by: Glauber Costa <glommer@cloudius-systems.com>
There's a CQL version constant in query processor. Use it when
advertising CQL version to clients.
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
This patch adds initial support for PREPARE and EXECUTE requests which
are used by the CQL binary protocol for prepared statements. The use of
prepared statement gives a nice 2.5x single core performance boost for
Urchin:
$ ./build/release/seastar --data data --smp 1
$ ./tools/bin/cassandra-stress write -mode cql3 simplenative -rate threads=32
Results:
op rate : 31728
partition rate : 31728
row rate : 31728
latency mean : 1.0
latency median : 0.9
latency 95th percentile : 1.8
latency 99th percentile : 1.8
latency 99.9th percentile : 5.6
latency max : 181.7
Total operation time : 00:00:30
END
$ ./tools/bin/cassandra-stress write -mode cql3 simplenative prepared -rate threads=32
Results:
op rate : 75033
partition rate : 75033
row rate : 75033
latency mean : 0.4
latency median : 0.4
latency 95th percentile : 0.7
latency 99th percentile : 0.8
latency 99.9th percentile : 3.4
latency max : 205.0
Total operation time : 00:00:30
END
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
There's a cyclic dependency between cql3 and transport namespaces when
we introduce prepared statements. The latter pulls
parsed_statement::prepared from the former. Break the cycle by using
a forward delcaration in cql_statement.hh.
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
Query processor needs to store prepared statements as part of a client
session for PREPARE and EXECUTE requests. Switch from unique_ptr to
shared_ptr in preparation for that.
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
s/database/distributed<database>/ everywhere.
Use simple distribution rules: writes are broadcast, reads are local.
This causes tremendous data duplication, but will change soon.
