Replica migration algorithm modified so that slaves never try to migrate
to masters that were never configured to have slaves in the past.
We want the algorithm to take care of masters that remained without
*working* slaves, but that used to have slaves according to the cluster
configuration.
Replica migration algorithm modified so that slaves never try to migrate
to masters that were never configured to have slaves in the past.
We want the algorithm to take care of masters that remained without
*working* slaves, but that used to have slaves according to the cluster
configuration.
Based on ideas documented in this blog post:
https://www.facebook.com/notes/facebook-engineering/three-optimization-tips-for-c/10151361643253920
The original code was modified to handle signed integers, reformetted to
fit inside the Redis code base, and was stress-tested with a program
in order to validate the implementation against snprintf().
Redis was measured to be measurably faster from the point of view of
clients in real-world operations because of this change, since sometimes
number to string conversion is used extensively (for example every time
a GET results into an integer encoded object to be returned to the
user).
Based on ideas documented in this blog post:
https://www.facebook.com/notes/facebook-engineering/three-optimization-tips-for-c/10151361643253920
The original code was modified to handle signed integers, reformetted to
fit inside the Redis code base, and was stress-tested with a program
in order to validate the implementation against snprintf().
Redis was measured to be measurably faster from the point of view of
clients in real-world operations because of this change, since sometimes
number to string conversion is used extensively (for example every time
a GET results into an integer encoded object to be returned to the
user).
This is just a quickfix, for the nature of the test the right way to fix
it is to average the error of N runs, since otherwise it is always
possible to get a false positive with a bad run, or to minimize too much
this possibility we may end testing with too much "large" error ranges.
This is just a quickfix, for the nature of the test the right way to fix
it is to average the error of N runs, since otherwise it is always
possible to get a false positive with a bad run, or to minimize too much
this possibility we may end testing with too much "large" error ranges.
The user @kjmph provided excellent ideas to improve speed of ZUNIONSTORE
(in certain cases by many order of magnitude), together with an
implementation of the ideas.
While the ideas were sounding, the implementation could be improved both
in terms of speed and clearness, so that's my attempt at reimplementing
the speedup proposed, trying to improve by directly using just a
dictionary with an embedded score inside, and reusing the single-pass
aggregate + order-later approach.
Note that you can't apply this commit without applying the previous
commit in this branch that adds a double in the dictEntry value union.
Issue #1786.
The user @kjmph provided excellent ideas to improve speed of ZUNIONSTORE
(in certain cases by many order of magnitude), together with an
implementation of the ideas.
While the ideas were sounding, the implementation could be improved both
in terms of speed and clearness, so that's my attempt at reimplementing
the speedup proposed, trying to improve by directly using just a
dictionary with an embedded score inside, and reusing the single-pass
aggregate + order-later approach.
Note that you can't apply this commit without applying the previous
commit in this branch that adds a double in the dictEntry value union.
Issue #1786.
For non-empty masters, CLUSTER RESET is denied, and the user requires to
start to reset a node by explicitly clearing it with FLUSHALL.
However CLUSTER RESET when executed with slaves don't have this
restrictions since data is just a replica of the master, and with
read-only slaves it is also not possible to remove the data set. However
the node was turned from slave to master after a reset, without touching
the old slave data. This is 99.99% of times not appropriate and forces
full resets to follow this path to work with both slave and master
nodes:
FLUSHALL
CLUSTER RESET HARD
FLUSHALL
Since we need the first flushall for masters, and the second for slaves.
This commit changes the behavior so that CLUSTER RESET removes the data set
of a slave node during a reset, in the moment it gets turned into a master,
so the new pattern is simply:
FLUSHALL (that may fail for slaves)
CLUSTER RESET
For non-empty masters, CLUSTER RESET is denied, and the user requires to
start to reset a node by explicitly clearing it with FLUSHALL.
However CLUSTER RESET when executed with slaves don't have this
restrictions since data is just a replica of the master, and with
read-only slaves it is also not possible to remove the data set. However
the node was turned from slave to master after a reset, without touching
the old slave data. This is 99.99% of times not appropriate and forces
full resets to follow this path to work with both slave and master
nodes:
FLUSHALL
CLUSTER RESET HARD
FLUSHALL
Since we need the first flushall for masters, and the second for slaves.
This commit changes the behavior so that CLUSTER RESET removes the data set
of a slave node during a reset, in the moment it gets turned into a master,
so the new pattern is simply:
FLUSHALL (that may fail for slaves)
CLUSTER RESET
