Examples:
redis 127.0.0.1:6379> debug cmdkeys set foo bar
1) "foo"
redis 127.0.0.1:6379> debug cmdkeys mget a b c
1) "a"
2) "b"
3) "c"
redis 127.0.0.1:6379> debug cmdkeys zunionstore foo 2 a b
1) "a"
2) "b"
3) "foo"
redis 127.0.0.1:6379> debug cmdkeys ping
(empty list or set)
There is the exception of a "constant" BY pattern that is used in order
to signal to don't sort at all. In this case no lookup is needed so it
is possible to support this case in Cluster mode.
Previously we used zunionInterGetKeys(), however after this function was
fixed to account for the destination key (not needed when the API was
designed for "diskstore") the two set of commands can no longer be served
by an unique keys-extraction function.
This API originated from the "diskstore" experiment, not for Redis
Cluster itself, so there were legacy/useless things trying to
differentiate between keys that are going to be overwritten and keys
that need to be fetched from disk (preloaded).
All useless with Cluster, so removed with the result of code
simplification.
The code was already correct but it was using that bindaddr[0] is set to
NULL as a side effect of current implementation if no bind address is
configured. This is not guarnteed to hold true in the future.
When node-timeout is too small, in the order of a few milliseconds,
there is no way the voting process can terminate during that time, so we
set a lower limit for the failover timeout of two seconds.
The retry time is set to two times the failover timeout time, so it is
at least 4 seconds.
The previous implementation wasn't taking into account
the storage key in position 1 being a requirement (it
was only counting the source keys in positions 3 to N).
Fixesantirez/redis#1581
This value needs to be set to zero (in addition to
stat_numcommands) or else people may see
a negative operations per second count after they
run CONFIG RESETSTAT.
Fixesantirez/redis#1577
The first address specified as a bind parameter
(server.bindaddr[0]) gets used as the source IP
for cluster communication.
If no bind address is specified by the user, the
behavior is unchanged.
This patch allows multiple Redis Cluster instances
to communicate when running on the same interface
of the same host.
The default cluster control port is 10,000 ports higher than
the base Redis port. If Redis is started on a too-high port,
Cluster can't start and everything will exit later anyway.
Report the actual port used for the listening attempt instead of
server.port.
Originally, Redis would just listen on server.port.
But, with clustering, Redis uses a Cluster Port too,
so we can't say server.port is always where we are listening.
If you tried to launch Redis with a too-high port number (any
port where Port+10000 > 65535), Redis would refuse to start, but
only print an error saying it can't connect to the Redis port.
This patch fixes much confusions.
This commit sets the failover timeout to 30 seconds instead of the 180
seconds default, and allows to reconfigure multiple slaves at the same
time.
This makes tests less sensible to timing, with the result that there are
less false positives due to normal behaviors that require time to
succeed or to be retried.
However the long term solution is probably some way in order to detect
when a test failed because of timing issues (for example split brain
during leader election) and retry it.
Sentinel needs to avoid split brain conditions due to multiple sentinels
trying to get voted at the exact same time.
So far some desynchronization was provided by fluctuating server.hz,
that is the frequency of the timer function call. However the
desynchonization provided in this way was not enough when using many
Sentinel instances, especially when a large quorum value is used in
order to force a greater degree of agreement (more than N/2+1).
It was verified that it was likely to trigger a split brain
condition, forcing the system to try again after a timeout.
Usually the system will succeed after a few retries, but this is not
optimal.
This commit desynchronizes instances in a more effective way to make it
likely that the first attempt will be successful.
This is still code to rework in order to use agreement to obtain a new
configEpoch when a slot is migrated, however this commit handles the
special case that happens when the nodes are just started and everybody
has a configEpoch of 0. In this special condition to have the maximum
configEpoch is not enough as the special epoch 0 is not unique (all the
others are).
This does not fixes the intrinsic race condition of a failover happening
while we are resharding, that will be addressed later.
used_memory_peak only updates in serverCron every server.hz,
but Redis can use more memory and a user can request memory
INFO before used_memory_peak gets updated in the next
cron run.
This patch updates used_memory_peak to the current
memory usage if the current memory usage is higher
than the recorded used_memory_peak value.
(And it only calls zmalloc_used_memory() once instead of
twice as it was doing before.)
This commit reworks the redis-cli --bigkeys command to provide more
information about our progress as well as output summary information
when we're done.
- We now show an approximate percentage completion as we go
- Hiredis pipelining is used for TYPE and SIZE retreival
- A summary of keyspace distribution and overall breakout at the end
