- 30 Apr, 2013 4 commits
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antirez authored
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antirez authored
Tilt mode was too aggressive (not processing INFO output), this resulted in a few problems: 1) Redirections were not followed when in tilt mode. This opened a window to misinform clients about the current master when a Sentinel was in tilt mode and a fail over happened during the time it was not able to update the state. 2) It was possible for a Sentinel exiting tilt mode to detect a false fail over start, if a slave rebooted with a wrong configuration about at the same time. This used to happen since in tilt mode we lose the information that the runid changed (reboot). Now instead the Sentinel in tilt mode will still remove the instance from the list of slaves if it changes state AND runid at the same time. Both are edge conditions but the changes should overall improve the reliability of Sentinel.
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antirez authored
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antirez authored
We used to always turn a master into a slave if the DEMOTE flag was set, as this was a resurrecting master instance. However the following race condition is possible for a Sentinel that got partitioned or internal issues (tilt mode), and was not able to refresh the state in the meantime: 1) Sentinel X is running, master is instance "A". 3) "A" fails, sentinels will promote slave "B" as master. 2) Sentinel X goes down because of a network partition. 4) "A" returns available, Sentinels will demote it as a slave. 5) "B" fails, other Sentinels will promote slave "A" as master. 6) At this point Sentinel X comes back. When "X" comes back he thinks that: "B" is the master. "A" is the slave to demote. We want to avoid that Sentinel "X" will demote "A" into a slave. We also want that Sentinel "X" will detect that the conditions changed and will reconfigure itself to monitor the right master. There are two main ways for the Sentinel to reconfigure itself after this event: 1) If "B" is reachable and already configured as a slave by other sentinels, "X" will perform a redirection to "A". 2) If there are not the conditions to demote "A", the fact that "A" reports to be a master will trigger a failover detection in "X", that will end into a reconfiguraiton to monitor "A". However if the Sentinel was not reachable, its state may not be updated, so in case it titled, or was partiitoned from the master instance of the slave to demote, the new implementation waits some time (enough to guarantee we can detect the new INFO, and new DOWN conditions). If after some time still there are not the right condiitons to demote the instance, the DEMOTE flag is cleared.
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- 24 Apr, 2013 4 commits
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antirez authored
Sentinel redirected to the master if the instance changed runid or it was the first time we got INFO, and a role change was detected from master to slave. While this is a good idea in case of slave->master, since otherwise we could detect a failover without good reasons just after a reboot with a slave with a wrong configuration, in the case of master->slave transition is much better to always perform the redirection for the following reasons: 1) A Sentinel may go down for some time. When it is back online there is no other way to understand there was a failover. 2) Pointing clients to a slave seems to be always the wrong thing to do. 3) There is no good rationale about handling things differently once an instance is rebooted (runid change) in that case.
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antirez authored
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antirez authored
This prevents the kernel from putting too much stuff in the output buffers, doing too heavy I/O all at once. So the goal of this commit is to split the disk pressure due to the AOF rewrite process into smaller spikes. Please see issue #1019 for more information.
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antirez authored
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- 22 Apr, 2013 1 commit
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antirez authored
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- 19 Apr, 2013 1 commit
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antirez authored
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- 11 Apr, 2013 2 commits
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antirez authored
Previously redis-cli never tried to raise an error when an unrecognized switch was encountered, as everything after the initial options is to be transmitted to the server. However this is too liberal, as there are no commands starting with "-". So the new behavior is to produce an error if there is an unrecognized switch starting with "-". This should not break past redis-cli usages but should prevent broken options to be silently discarded. As far the first token not starting with "-" is encountered, all the rest is considered to be part of the command, so you cna still use strings starting with "-" as values, like in: redis-cli --port 6380 set foo --my-value
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antirez authored
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- 03 Apr, 2013 1 commit
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antirez authored
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- 02 Apr, 2013 1 commit
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antirez authored
When a BGSAVE fails, Redis used to flood itself trying to BGSAVE at every next cron call, that is either 10 or 100 times per second depending on configuration and server version. This commit does not allow a new automatic BGSAVE attempt to be performed before a few seconds delay (currently 5). This avoids both the auto-flood problem and filling the disk with logs at a serious rate. The five seconds limit, considering a log entry of 200 bytes, will use less than 4 MB of disk space per day that is reasonable, the sysadmin should notice before of catastrofic events especially since by default Redis will stop serving write queries after the first failed BGSAVE. This fixes issue #849
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- 29 Mar, 2013 2 commits
- 28 Mar, 2013 4 commits
- 27 Mar, 2013 4 commits
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antirez authored
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antirez authored
MULTI/EXEC is now propagated to the AOF / Slaves only once we encounter the first command that is not a read-only one inside the transaction. The old behavior was to always propagate an empty MULTI/EXEC block when the transaction was composed just of read only commands, or even completely empty. This created two problems: 1) It's a bandwidth waste in the replication link and a space waste inside the AOF file. 2) We used to always increment server.dirty to force the propagation of the EXEC command, resulting into triggering RDB saves more often than needed. Note: even read-only commands may also trigger writes that will be propagated, when we access a key that is found expired and Redis will synthesize a DEL operation. However there is no need for this to stay inside the transaction itself, but only to be ordered. So for instance something like: MULTI GET foo SET key zap EXEC May be propagated into: DEL foo MULTI SET key zap EXEC While the DEL is outside the transaction, the commands are delivered in the right order and it is not possible for other commands to be inserted between DEL and MULTI.
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antirez authored
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antirez authored
The behavior is the same, but the code is now cleaner and uses the proper interface instead of dealing directly with AOF/replication functions.
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- 26 Mar, 2013 1 commit
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antirez authored
Fixes issue #1024.
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- 25 Mar, 2013 2 commits
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NanXiao authored
Fix bug in configGetCommand function: get correct masterauth value.
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antirez authored
Redis-tools is a connection of tools no longer mantained that was intented as a way to economically make sense of Redis in the pre-vmware sponsorship era. However there was a nice redis-stat utility, this commit imports one of the functionalities of this tool here in redis-cli as it seems to be pretty useful. Usage: redis-cli --stat The output is similar to vmstat in the format, but with Redis specific stuff of course. From the point of view of the monitored instance, only INFO is used in order to grab data.
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- 13 Mar, 2013 3 commits
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antirez authored
server.repl_down_since used to be initialized to the current time at startup. This is wrong since the replication never started. Clients testing this filed to check if data is uptodate should never believe data is recent if we never ever connected to our master.
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antirez authored
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Damian Janowski authored
This fixes cases where the RDB file does exist but can't be accessed for any reason. For instance, when the Redis process doesn't have enough permissions on the file.
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- 12 Mar, 2013 2 commits
- 11 Mar, 2013 8 commits
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antirez authored
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antirez authored
activeExpireCycle() tries to test just a few DBs per iteration so that it scales if there are many configured DBs in the Redis instance. However this commit makes it a bit smarter when one a few of those DBs are under expiration pressure and there are many many keys to expire. What we do is to remember if in the last iteration had to return because we ran out of time. In that case the next iteration we'll test all the configured DBs so that we are sure we'll test again the DB under pressure. Before of this commit after some mass-expire in a given DB the function tested just a few of the next DBs, possibly empty, a few per iteration, so it took a long time for the function to reach again the DB under pressure. This resulted in a lot of memory being used by already expired keys and never accessed by clients.
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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
This small number of DBs is set to 16 so actually in the default configuraiton Redis should behave exactly like in the past. However the difference is that when the user configures a very large number of DBs we don't do an O(N) operation, consuming a non trivial amount of CPU per serverCron() iteration.
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antirez authored
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