PING can now be called with an additional arugment, behaving exactly
like the ECHO command. PING can now also be called in Pub/Sub mode (with
one more more subscriptions to channels / patterns) in order to trigger
the delivery of an asynchronous pong message with the optional payload.
This fixes issue #420.
The code tested many times if a client had active Pub/Sub subscriptions
by checking the length of a list and dictionary where the patterns and
channels are stored. This was substituted with a client flag called
REDIS_PUBSUB that is simpler to test for. Moreover in order to manage
this flag some code was refactored.
This commit is believed to have no effects in the behavior of the
server.
Previously, the command definition for the OBJECT command specified
a minimum of two args (and that it was variadic), which meant that
if you sent this:
OBJECT foo
When cluster was enabled, it would result in an assertion/SEGFAULT
when Redis was attempting to extract keys.
It appears that OBJECT is not variadic, and only ever takes 3 args.
https://gist.github.com/michael-grunder/25960ce1508396d0d36a
We introduce the distinction between slow and fast commands since those
are two different sources of latency. An O(1) or O(log N) command without
side effects (can't trigger deletion of large objects as a side effect of
its execution) if delayed is a symptom of inherent latency of the system.
A non-fast command (commands that may run large O(N) computations) if
delayed may just mean that the user is executing slow operations.
The advices LATENCY should provide in this two different cases are
different, so we log the two classes of commands in a separated way.
This fixes detection of wrong subcommand (that resulted in the default
all-commands output instead) and allows COMMAND INFO to be called
without arguments (resulting into an empty array) which is useful in
programmtically generated calls like the following (in Ruby):
redis.commands("command","info",*mycommands)
Note: mycommands may be empty.
