1. 31 Mar, 2014 1 commit
    • antirez's avatar
      HyperLogLog: use LINEARCOUNTING up to 3m. · 60e60f4e
      antirez authored
      The HyperLogLog original paper suggests using LINEARCOUNTING for
      cardinalities < 2.5m, however for P=14 the median / max error
      curves show that a value of '3' is the best pick for m = 16384.
      60e60f4e
  2. 30 Mar, 2014 2 commits
    • antirez's avatar
      HyperLogLog approximated cardinality caching. · 307a1899
      antirez authored
      The more we add elements to an HyperLogLog counter, the smaller is
      the probability that we actually update some register.
      
      From this observation it is easy to see how it is possible to use
      caching of a previously computed cardinality and reuse it to serve
      HLLCOUNT queries as long as no register was updated in the data
      structure.
      
      This commit does exactly this by using just additional 8 bytes for the
      data structure to store a 64 bit unsigned integer value cached
      cardinality. When the most significant bit of the 64 bit integer is set,
      it means that the value computed is no longer usable since at least a
      single register was modified and we need to recompute it at the next
      call of HLLCOUNT.
      
      The value is always stored in little endian format regardless of the
      actual CPU endianess.
      307a1899
    • antirez's avatar
      String value unsharing refactored into proper function. · 543ede03
      antirez authored
      All the Redis functions that need to modify the string value of a key in
      a destructive way (APPEND, SETBIT, SETRANGE, ...) require to make the
      object unshared (if refcount > 1) and encoded in raw format (if encoding
      is not already REDIS_ENCODING_RAW).
      
      This was cut & pasted many times in multiple places of the code. This
      commit puts the small logic needed into a function called
      dbUnshareStringValue().
      543ede03
  3. 29 Mar, 2014 5 commits
  4. 28 Mar, 2014 11 commits
  5. 27 Mar, 2014 2 commits
  6. 26 Mar, 2014 3 commits
  7. 25 Mar, 2014 6 commits
    • antirez's avatar
      Cluster: CLUSTER SETSLOT implementation comment updated. · eb746ec4
      antirez authored
      Update the comment since the implementation details changed.
      eb746ec4
    • antirez's avatar
      Cluster: redis-trib cluster allocation more even across nodes. · 0064b1a5
      antirez authored
      redis-trib used to allocate slots not considering fractions of nodes
      when computing the slots_per_node amount. So the fractional part was
      carried over till the end of the allocation, where the last node
      received a few more slots than any other (or a lot more if the cluster
      was composed of many nodes).
      
      The computation was changed to allocate slots more evenly when they are
      not exactly divisible for the number of masters we have.
      0064b1a5
    • antirez's avatar
      Cluster: configEpoch collisions resolution. · 6c527a89
      antirez authored
      The slave election in Redis Cluster guarantees that slaves promoted to
      masters always end with unique config epochs, however failures during
      manual reshardings, software bugs and operational errors may in theory
      cause two nodes to have the same configEpoch.
      
      This commit introduces a mechanism to eventually always end with different
      configEpochs if a collision ever happens.
      
      As a (wanted) side effect, this also ensures that after a new cluster
      is created, all nodes will end with a different configEpoch automatically.
      6c527a89
    • antirez's avatar
      Cluster: stay within 80 cols. · c1041c57
      antirez authored
      c1041c57
    • antirez's avatar
      Fix off by one bug in freeMemoryIfNeeded() eviction pool. · 6540e9ee
      antirez authored
      Bug found by the continuous integration test running the Redis
      with valgrind:
      
      ==6245== Invalid read of size 8
      ==6245==    at 0x4C2DEEF: memcpy@GLIBC_2.2.5 (mc_replace_strmem.c:876)
      ==6245==    by 0x41F9E6: freeMemoryIfNeeded (redis.c:3010)
      ==6245==    by 0x41D2CC: processCommand (redis.c:2069)
      
      memmove() size argument was accounting for an extra element, going
      outside the bounds of the array.
      6540e9ee
    • antirez's avatar
      adjustOpenFilesLimit() refactoring. · 6e33c908
      antirez authored
      In this commit:
      * Decrement steps are semantically differentiated from the reserved FDs.
        Previously both values were 32 but the meaning was different.
      * Make it clear that we save setrlimit errno.
      * Don't explicitly handle wrapping of 'f', but prevent it from
        happening.
      * Add comments to make the function flow more readable.
      
      This integrates PR #1630
      6e33c908
  8. 24 Mar, 2014 10 commits
    • antirez's avatar
      Fixed undefined variable value with certain code paths. · 35667d75
      antirez authored
      In sentinelFlushConfig() fd could be undefined when the following if
      statement was true:
      
              if (rewrite_status == -1) goto werr;
      
      This could cause random file descriptors to get closed.
      35667d75
    • Matt Stancliff's avatar
      Use LRU_CLOCK() instead of function getLRUClock() · 78782ed5
      Matt Stancliff authored
      lookupKey() uses LRU_CLOCK(), so it seems object
      creation should use LRU_CLOCK() too.
      78782ed5
    • Matt Stancliff's avatar
      42904551
    • Matt Stancliff's avatar
      Fix data loss when save AOF/RDB with no free space · b47b343f
      Matt Stancliff authored
      Previously, the (!fp) would only catch lack of free space
      under OS X.  Linux waits to discover it can't write until
      it actually writes contents to disk.
      
      (fwrite() returns success even if the underlying file
      has no free space to write into.  All the errors
      only show up at flush/sync/close time.)
      
      Fixes antirez/redis#1604
      b47b343f
    • Matt Stancliff's avatar
      Fix potentially incorrect errno usage · 386a4694
      Matt Stancliff authored
      errno may be reset by the previous call to redisLog, so capture
      the original value for proper error reporting.
      386a4694
    • Matt Stancliff's avatar
      Add REDIS_MIN_RESERVED_FDS define for open fds · 3b54ee6e
      Matt Stancliff authored
      Also update the original REDIS_EVENTLOOP_FDSET_INCR to
      include REDIS_MIN_RESERVED_FDS. REDIS_EVENTLOOP_FDSET_INCR
      exists to make sure more than (maxclients+RESERVED) entries
      are allocated, but we can only guarantee that if we include
      the current value of REDIS_MIN_RESERVED_FDS as a minimum
      for the INCR size.
      3b54ee6e
    • Matt Stancliff's avatar
      Cluster: Restore proper trib master iteration · e942f3ce
      Matt Stancliff authored
      This got removed in 2e5c394f during a new feature addition.
      
      The prior commit had "break if masters.length == masters_count"
      but we are guaranteed to aready have that condition met since
      otherwise we would haven't gotten this far.
      
      Without this break statement, it's possible some masters may
      be forgotten and have zero replicas while other masters have
      more than their requested number of replicas.
      
      Thanks to carlos for pointing out this regression at:
      https://groups.google.com/forum/#!topic/redis-db/_WVVqDw5B7c
      e942f3ce
    • Matt Stancliff's avatar
      Cluster: Fix trib create when masters==replicas · df4bdbf6
      Matt Stancliff authored
      This bug was introduced in 2e5c394f during a refactor.
      
      It took me a while to understand what was going on with
      the code, so I've refactored it further by:
        - Replacing boolean values with meaningful symbols
        - Replacing 'i' with a meaningful variable name
        - Adding the proper abort check
        - Factoring out now duplicated conditionals
        - Adding optional verbose logging (we're inside *four*
          different looping constructs, so it takes a while to
          figure out where all the moving parts are)
        - Updating comment for the section
      
      This fixes a problem when the number of master instances
      equaled the number of replica instances.  Before, when
      there were equal numbers of both, nodes_count would go to
      zero, but the while loop would spin in i < @replicas because
      i would never be updated (because the nodes_list of each ip
      was length == 0, which triggered an endless loop of
      next -> i = 0 -> 0 < 1? -> true -> next -> i = 0 ...)
      
      Thanks to carlo who found this problem at:
      https://groups.google.com/forum/#!topic/redis-db/_WVVqDw5B7c
      df4bdbf6
    • Matt Stancliff's avatar
      Fix infinite loop on startup if ulimit too low · 90b84421
      Matt Stancliff authored
      Fun fact: rlim_t is an unsigned long long on all platforms.
      
      Continually subtracting from a rlim_t makes it get smaller
      and smaller until it wraps, then you're up to 2^64-1.
      
      This was causing an infinite loop on Redis startup if
      your ulimit was extremely (almost comically) low.
      
      The case of (f > oldlimit) would never be met in a case like:
      
          f = 150
          while (f > 20) f -= 128
      
      Since f is unsigned, it can't go negative and would
      take on values of:
      
          Iteration 1: 150 - 128 => 22
          Iteration 2:  22 - 128 => 18446744073709551510
          Iterations 3-∞: ...
      
      To catch the wraparound, we use the previous value of f
      stored in limit.rlimit_cur.  If we subtract from f and
      get a larger number than the value it had previously,
      we print an error and exit since we don't have enough
      file descriptors to help the user at this point.
      
      Thanks to @bs3g for the inspiration to fix this problem.
      Patches existed from @bs3g at antirez#1227, but I needed to repair a few other
      parts of Redis simultaneously, so I didn't get a chance to use them.
      90b84421
    • Matt Stancliff's avatar
      Improve error handling around setting ulimits · 4a25983f
      Matt Stancliff authored
      The log messages about open file limits have always
      been slightly opaque and confusing.  Here's an attempt to
      fix their wording, detail, and meaning.  Users will have a
      better understanding of how to fix very common problems
      with these reworded messages.
      
      Also, we handle a new error case when maxclients becomes less
      than one, essentially rendering the server unusable.  We
      now exit on startup instead of leaving the user with a server
      unable to handle any connections.
      
      This fixes antirez#356 as well.
      4a25983f