- 24 Mar, 2014 5 commits
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Matt Stancliff authored
Everywhere in the Redis code base, maxclients is treated as an int with (int)maxclients or `maxclients = atoi(source)`, so let's make maxclients an int. This fixes a bug where someone could specify a negative maxclients on startup and it would work (as well as set maxclients very high) because: unsigned int maxclients; char *update = "-300"; maxclients = atoi(update); if (maxclients < 1) goto fail; But, (maxclients < 1) can only catch the case when maxclients is exactly 0. maxclients happily sets itself to -300, which isn't -300, but rather 4294966996, which isn't < 1, so... everything "worked." maxclients config parsing checks for the case of < 1, but maxclients CONFIG SET parsing was checking for case of < 0 (allowing maxclients to be set to 0). CONFIG SET parsing is now updated to match config parsing of < 1. It's tempting to add a MINIMUM_CLIENTS define, but... I didn't. These changes were inspired by antirez#356, but this doesn't fix that issue.
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antirez authored
Obtaining the RSS (Resident Set Size) info is slow in Linux and OSX. This slowed down the generation of the INFO 'memory' section. Since the RSS does not require to be a real-time measurement, we now sample it with server.hz frequency (10 times per second by default) and use this value both to show the INFO rss field and to compute the fragmentation ratio. Practically this does not make any difference for memory profiling of Redis but speeds up the INFO call significantly.
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antirez authored
For small content the function now tries to use a static buffer to avoid a malloc/free cycle that is too costly when the function is used in the context of performance critical code path such as INFO output generation. This change was verified to have positive effects in the execution speed of the INFO command.
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antirez authored
Uname was profiled to be a slow syscall. It produces always the same output in the context of a single execution of Redis, so calling it at every INFO output generation does not make too much sense. The uname utsname structure was modified as a static variable. At the same time a static integer was added to check if we need to call uname the first time.
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antirez authored
sdscatvprintf() uses a loop where it tries to output the formatted string in a buffer of the initial length, if there was not enough room, a buffer of doubled size is tried and so forth. The initial guess for the buffer length was very poor, an hardcoded "16". This caused the printf to be processed multiple times without a good reason. Given that printf functions are already not fast, the overhead was significant. The new heuristic is to use a buffer 4 times the length of the format buffer, and 32 as minimal size. This appears to be a good balance for typical uses of the function inside the Redis code base. This change improved INFO command performances 3 times.
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- 21 Mar, 2014 3 commits
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antirez authored
This is a program useful to evaluate the Redis LRU algorithm behavior.
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antirez authored
Thanks to Matt Stancliff for noticing this error. It was in the original code but somehow I managed to remove the change from the commit...
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antirez authored
This is safer as by default maxmemory should just set a memory limit without any key to be deleted, unless the policy is set to something more relaxed.
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- 20 Mar, 2014 11 commits
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antirez authored
There were 2 spare bits inside the Redis object structure that are now used in order to enlarge 4x the range of the LRU field. At the same time the resolution was improved from 10 to 1 second: this still provides 194 days before the LRU counter overflows (restarting from zero). This is not a problem since it only causes lack of eviction precision for objects not touched for a very long time, and the lack of precision is only temporary.
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antirez authored
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antirez authored
The eviction quality degradates a bit in my tests, but since the API is faster, it allows to raise the number of samples, and overall is a win.
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antirez authored
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antirez authored
This new function is useful to get a number of random entries from an hash table when we just need to do some sampling without particularly good distribution. It just jumps at a random place of the hash table and returns the first N items encountered by scanning linearly. The main usefulness of this function is to speedup Redis internal sampling of the key space, for example for key eviction or expiry.
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antirez authored
This is an improvement over the previous eviction algorithm where we use an eviction pool that is persistent across evictions of keys, and gets populated with the best candidates for evictions found so far. It allows to approximate LRU eviction at a given number of samples better than the previous algorithm used.
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antirez authored
estimateObjectIdleTime() returns a value in milliseconds now, so we need to scale the output of OBJECT IDLETIME to seconds.
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antirez authored
For testing purposes it is handy to have a very high resolution of the LRU clock, so that it is possible to experiment with scripts running in just a few seconds how the eviction algorithms works. This commit allows Redis to use the cached LRU clock, or a value computed on demand, depending on the resolution. So normally we have the good performance of a precomputed value, and a clock that wraps in many days using the normal resolution, but if needed, changing a define will switch behavior to an high resolution LRU clock.
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antirez authored
The padding field was totally useless: removed.
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antirez authored
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antirez authored
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- 19 Mar, 2014 1 commit
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antirez authored
Now CONFIG RESETSTAT makes sure to reset all the fields, and in the future it will be simpler to avoid missing new fields.
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- 18 Mar, 2014 6 commits
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antirez authored
Test sentinel.tilt condition on top and return if it is true. This allows to remove the check for the tilt condition in the remaining code paths of the function.
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antirez authored
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antirez authored
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antirez authored
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antirez authored
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antirez authored
addReplySentinelRedisInstance() modified so that this field is displayed for all the kind of instances: Sentinels, Masters, Slaves.
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- 17 Mar, 2014 1 commit
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antirez authored
Failure detection in Sentinel is ping-pong based. It used to work by remembering the last time a valid PONG reply was received, and checking if the reception time was too old compared to the current current time. PINGs were sent at a fixed interval of 1 second. This works in a decent way, but does not scale well when we want to set very small values of "down-after-milliseconds" (this is the node timeout basically). This commit reiplements the failure detection making a number of changes. Some changes are inspired to Redis Cluster failure detection code: * A new last_ping_time field is added in representation of instances. If non zero, we have an active ping that was sent at the specified time. When a valid reply to ping is received, the field is zeroed again. * last_ping_time is not reset when we reconnect the link or send a new ping, so from our point of view it represents the time we started waiting for the instance to reply to our pings without receiving a reply. * last_ping_time is now used in order to check if the instance is timed out. This means that we can have a node timeout of 100 milliseconds and yet the system will work well since the new check is not bound to the period used to send pings. * Pings are now sent every second, or often if the value of down-after-milliseconds is less than one second. With a lower limit of 10 HZ ping frequency. * Link reconnection code was improved. This is used in order to try to reconnect the link when we are at 50% of the node timeout without a valid reply received yet. However the old code triggered unnecessary reconnections when the node timeout was very small. Now that should be ok. The new code passes the tests but more testing is needed and more unit tests stressing the failure detector, so currently this is merged only in the unstable branch.
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- 15 Mar, 2014 1 commit
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antirez authored
This makes debugging / monitoring of Sentinels simpler since you can identify sentinels in CLIENT LIST output of Redis instances.
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- 14 Mar, 2014 5 commits
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Salvatore Sanfilippo authored
Fix segfault from accessing array out of bounds
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Matt Stancliff authored
argc == 2; argv[2] == crash
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antirez authored
Sentinel's main safety argument is that there are no two configurations for the same master with the same version (configuration epoch). For this to be true Sentinels require to be authorized by a majority. Additionally Sentinels require to do two important things: * Never vote again for the same epoch. * Never exchange an old vote for a fresh one. The first prerequisite, in a crash-recovery system model, requires to persist the master->leader_epoch on durable storage before to reply to messages. This was not the case. We also make sure to persist the current epoch in order to never reply to stale votes requests from other Sentinels, after a recovery. The configuration is persisted by making use of fsync(), this is considered in the context of this code a good enough guarantee that after a restart our durable state is restored, however this may not always be the case depending on the kind of hardware and operating system used.
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antirez authored
Now the way HELLO messages are received is unified. Now it is no longer needed for Sentinels to converge to the higher configuration for a master to be able to chat via some Redis instance, the are able to directly exchanges configurations. Note that this commit does not include the (trivial) change needed to send HELLO messages to Sentinel instances as well, since for an error I committed the change in the previous commit that refactored hello messages processing into a separated function.
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antirez authored
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- 13 Mar, 2014 2 commits
- 11 Mar, 2014 5 commits
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antirez authored
See issue #1593. Thanks to @badboy for suggesting the direct client.call fix.
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antirez authored
Example: ./redis-trib.rb call 192.168.1.11:7000 config get cluster-node-timeout
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antirez authored
Example: if the user will try to configure a cluster with 9 nodes, asking for 1 slave for master, redis-trib will configure a 4 masters cluster with 1 slave each as usually, but this time will assign the spare node as a slave of one of the masters.
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antirez authored
The UPDATE message contains the configEpoch of the node configuration advertised in the packet. Update it if needed.
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antirez authored
By manually modifying nodes configurations in random ways, it is possible to create the following scenario: A is serving keys for slot 10 B is manually configured to serve keys for slot 10 A receives an update from B (or another node) where it is informed that the slot 10 is now claimed by B with a greater configuration epoch, however A still has keys from slot 10. With this commit A will put the slot in error setting it in IMPORTING state, so that redis-trib can detect the issue.
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