Serializing an instance of a redis-cluster connection with its nodes
can take more than 1 seconds on extremely slow hardware.
See issue #220 for reference.
This optimization makes it possible to fetch the slots map directly
from the server indicated by the -MOVED response eliminating the need
to use a random node in the pool, which in turn could require Predis
to open a new and useless connection.
This is a more sane default as it allows users to indicate only a few
servers of the whole cluster composition, while it previously required
a more complex configuration of the client using client options.
This feature can be disabled using the "enableAutoSlotsMap()" method.
This change is possible because, after a few changes in redis-cluster,
our default cluster strategy used for client side sharding and the one
used for redis-cluster turned out to be exactly the same, except for
the hashing function used to calculate distribution.
Actually some checks used to enforce correctness are redundant in the
context of redis-cluster (e.g. the one used to make sure that keys in
requests performing cross-keys operations will hash to the same slot,
which is performed by the server) so we could also add a more dumb and
permissive cluster strategy that relies on checks performed by Redis.
Differently to v0.8, the strategy for client-side sharding now uses
the same rules for extracting hash tags from keys especially when
empty tags are found in the string.
CLUSTER SLOTS returns a structured response easier to handle compared
to the bulk response of CLUSTER NODES which must be parsed making the
whole thing more fragile.
CLUSTER SLOTS has been added in Redis 3.0.0b7.
This is more consistent with the actual purpose of this method and
more in-line with a possible future change in the underlying command
used to retrieve the slots map if redis-cluster will implement the
CLUSTER SLOTS command.
* Renamed SingleConnectionInterface to NodeConnectionInterface since
this name is better and makes even more sense in the context of
cluster and replication scenarios.
* Moved specialized aggregate connections (the ones implementing both
predis and redis cluster and master/slave replication) in a newly
created Predis\Connection\Aggregate sub-namespace.
* Removed the "Connection" part from names of aggregate connection
interfaces in the Predis\Connection\Aggregate sub-namespace.
* Changed "Composable" to "Composite" in the name of interfaces and
classes that can use pluggable protocol processors.
Daniele Alessandri