1. 15 Mar, 2018 26 commits
  2. 14 Mar, 2018 1 commit
    • antirez's avatar
      Cluster: ability to prevent slaves from failing over their masters. · 432bf477
      antirez authored
      This commit, in some parts derived from PR #3041 which is no longer
      possible to merge (because the user deleted the original branch),
      implements the ability of slaves to have a special configuration
      preventing that they try to start a failover when the master is failing.
      
      There are multiple reasons for wanting this, and the feautre was
      requested in issue #3021 time ago.
      
      The differences between this patch and the original PR are the
      following:
      
      1. The flag is saved/loaded on the nodes configuration.
      2. The 'myself' node is now flag-aware, the flag is updated as needed
         when the configuration is changed via CONFIG SET.
      3. The flag name uses NOFAILOVER instead of NO_FAILOVER to be consistent
         with existing NOADDR.
      4. The redis.conf documentation was rewritten.
      
      Thanks to @deep011 for the original patch.
      432bf477
  3. 01 Mar, 2018 3 commits
  4. 28 Feb, 2018 1 commit
  5. 27 Feb, 2018 8 commits
    • antirez's avatar
    • antirez's avatar
      expireIfNeeded() comment: claim -> pretend. · b00c4ffa
      antirez authored
      b00c4ffa
    • charsyam's avatar
      refactoring-make-condition-clear-for-rdb · 76386c48
      charsyam authored
      76386c48
    • charsyam's avatar
      fix-out-of-index-range-for-redis-cli-findbigkey · 6168d5a1
      charsyam authored
      6168d5a1
    • antirez's avatar
      ae.c: insetad of not firing, on AE_BARRIER invert the sequence. · 956350ef
      antirez authored
      AE_BARRIER was implemented like:
      
          - Fire the readable event.
          - Do not fire the writabel event if the readable fired.
      
      However this may lead to the writable event to never be called if the
      readable event is always fired. There is an alterantive, we can just
      invert the sequence of the calls in case AE_BARRIER is set. This commit
      does that.
      956350ef
    • antirez's avatar
      AOF: fix a bug that may prevent proper fsyncing when fsync=always. · 75987431
      antirez authored
      In case the write handler is already installed, it could happen that we
      serve the reply of a query in the same event loop cycle we received it,
      preventing beforeSleep() from guaranteeing that we do the AOF fsync
      before sending the reply to the client.
      
      The AE_BARRIER mechanism, introduced in a previous commit, prevents this
      problem. This commit makes actual use of this new feature to fix the
      bug.
      75987431
    • antirez's avatar
      Cluster: improve crash-recovery safety after failover auth vote. · 533d0e03
      antirez authored
      Add AE_BARRIER to the writable event loop so that slaves requesting
      votes can't be served before we re-enter the event loop in the next
      iteration, so clusterBeforeSleep() will fsync to disk in time.
      Also add the call to explicitly fsync, given that we modified the last
      vote epoch variable.
      533d0e03
    • antirez's avatar
      ae.c: introduce the concept of read->write barrier. · 548e478e
      antirez authored
      AOF fsync=always, and certain Redis Cluster bus operations, require to
      fsync data on disk before replying with an acknowledge.
      In such case, in order to implement Group Commits, we want to be sure
      that queries that are read in a given cycle of the event loop, are never
      served to clients in the same event loop iteration. This way, by using
      the event loop "before sleep" callback, we can fsync the information
      just one time before returning into the event loop for the next cycle.
      This is much more efficient compared to calling fsync() multiple times.
      
      Unfortunately because of a bug, this was not always guaranteed: the
      actual way the events are installed was the sole thing that could
      control. Normally this problem is hard to trigger when AOF is enabled
      with fsync=always, because we try to flush the output buffers to the
      socekt directly in the beforeSleep() function of Redis. However if the
      output buffers are full, we actually install a write event, and in such
      a case, this bug could happen.
      
      This change to ae.c modifies the event loop implementation to make this
      concept explicit. Write events that are registered with:
      
          AE_WRITABLE|AE_BARRIER
      
      Are guaranteed to never fire after the readable event was fired for the
      same file descriptor. In this way we are sure that data is persisted to
      disk before the client performing the operation receives an
      acknowledged.
      
      However note that this semantics does not provide all the guarantees
      that one may believe are automatically provided. Take the example of the
      blocking list operations in Redis.
      
      With AOF and fsync=always we could have:
      
          Client A doing: BLPOP myqueue 0
          Client B doing: RPUSH myqueue a b c
      
      In this scenario, Client A will get the "a" elements immediately after
      the Client B RPUSH will be executed, even before the operation is persisted.
      However when Client B will get the acknowledge, it can be sure that
      "b,c" are already safe on disk inside the list.
      
      What to note here is that it cannot be assumed that Client A receiving
      the element is a guaranteed that the operation succeeded from the point
      of view of Client B.
      
      This is due to the fact that the barrier exists within the same socket,
      and not between different sockets. However in the case above, the
      element "a" was not going to be persisted regardless, so it is a pretty
      synthetic argument.
      548e478e
  6. 23 Feb, 2018 1 commit