1. 02 May, 2013 1 commit
  2. 30 Apr, 2013 2 commits
    • antirez's avatar
      Sentinel: changes to tilt mode. · e5ef85c4
      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.
      e5ef85c4
    • antirez's avatar
      ef05a78e
  3. 26 Apr, 2013 1 commit
    • antirez's avatar
      Sentinel: only demote old master into slave under certain conditions. · 48ede0d8
      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.
      48ede0d8
  4. 24 Apr, 2013 4 commits
    • antirez's avatar
      Sentinel: always redirect on master->slave transition. · 1965e22a
      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.
      1965e22a
    • antirez's avatar
      d264122f
    • antirez's avatar
      AOF: sync data on disk every 32MB when rewriting. · 336d722f
      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.
      336d722f
    • antirez's avatar
  5. 19 Apr, 2013 3 commits
  6. 11 Apr, 2013 2 commits
    • antirez's avatar
      redis-cli: raise error on bad command line switch. · f8ae70cf
      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
      f8ae70cf
    • antirez's avatar
      redis-cli: --latency-history mode implemented. · 0280c2f2
      antirez authored
      0280c2f2
  7. 09 Apr, 2013 4 commits
  8. 08 Apr, 2013 1 commit
    • antirez's avatar
      Cluster: properly send ping to nodes not pinged foro too much time. · f09b2508
      antirez authored
      In commit d728ec6d it was introduced the concept of sending a ping to
      every node not receiving a ping since node_timeout/2 seconds.
      However the code was located in a place that was not executed because of
      a previous conditional causing the loop to re-iterate.
      
      This caused false positives in nodes availability detection.
      
      The current code is still not perfect as a node may be detected to be in
      PFAIL state even if it does not reply for just node_timeout/2 seconds
      that is not correct. There is a plan to improve this code ASAP.
      f09b2508
  9. 04 Apr, 2013 4 commits
  10. 03 Apr, 2013 1 commit
  11. 02 Apr, 2013 2 commits
    • antirez's avatar
      Throttle BGSAVE attempt on saving error. · b237de33
      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
      b237de33
    • antirez's avatar
      Version bumped to 2.9.9. · b14fda7d
      antirez authored
      b14fda7d
  12. 29 Mar, 2013 1 commit
  13. 28 Mar, 2013 3 commits
  14. 27 Mar, 2013 1 commit
    • antirez's avatar
      DEBUG set-active-expire added. · 32a83c82
      antirez authored
      We need the ability to disable the activeExpireCycle() (active
      expired key collection) call for testing purposes.
      32a83c82
  15. 26 Mar, 2013 7 commits
    • antirez's avatar
      redis-trib: ClusterNode #info_string output modified. · 4fa30b78
      antirez authored
      The hope is that the new one is more readable.
      4fa30b78
    • antirez's avatar
      Allow SELECT while loading the DB. · df69155e
      antirez authored
      Fixes issue #1024.
      df69155e
    • antirez's avatar
      TTL / PTTL commands: two bugs fixed. · 873f328f
      antirez authored
      This commit fixes two corner cases for the TTL command.
      
      1) When the key was already logically expired (expire time older
      than current time) the command returned -1 instead of -2.
      
      2) When the key was existing and the expire was found to be exactly 0
      (the key was just about to expire), the command reported -1 (that is, no
      expire) instead of a TTL of zero (that is, about to expire).
      873f328f
    • antirez's avatar
      Flag PUBLISH as read-only in the command table. · 8bb5eb73
      antirez authored
      8bb5eb73
    • antirez's avatar
      Transactions: propagate MULTI/EXEC only when needed. · 71f3e743
      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.
      71f3e743
    • antirez's avatar
      02c269e2
    • antirez's avatar
      Transactions: use the propagate() API to propagate MULTI. · 2f497340
      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.
      2f497340
  16. 25 Mar, 2013 3 commits