1. 04 Oct, 2012 2 commits
    • Jokea's avatar
      Force expire all timer events when system clock skew is detected. · b7b2a1cc
      Jokea authored
      When system time changes back, the timer will not worker properly
      hence some core functionality of redis will stop working(e.g. replication,
      bgsave, etc). See issue #633 for details.
      
      The patch saves the previous time and when a system clock skew is detected,
      it will force expire all timers.
      
      Modiifed by @antirez: the previous time was moved into the eventLoop
      structure to make sure the library is still thread safe as long as you
      use different event loops into different threads (otherwise you need
      some synchronization). More comments added about the reasoning at the
      base of the patch, that's worth reporting here:
      
      /* If the system clock is moved to the future, and then set back to the
       * right value, time events may be delayed in a random way. Often this
       * means that scheduled operations will not be performed soon enough.
       *
       * Here we try to detect system clock skews, and force all the time
       * events to be processed ASAP when this happens: the idea is that
       * processing events earlier is less dangerous than delaying them
       * indefinitely, and practice suggests it is. */
      b7b2a1cc
    • antirez's avatar
      "Timeout receiving bulk data" error message modified. · f0b9f803
      antirez authored
      The new message now contains an hint about modifying the repl-timeout
      configuration directive if the problem persists.
      
      This should normally not be needed, because while the master generates
      the RDB file it makes sure to send newlines to the replication channel
      to prevent timeouts. However there are times when masters running on
      very slow systems can completely stop for seconds during the RDB saving
      process. In such a case enlarging the timeout value can fix the problem.
      
      See issue #695 for an example of this problem in an EC2 deployment.
      f0b9f803
  2. 03 Oct, 2012 1 commit
    • antirez's avatar
      "SORT by nosort" (skip sorting) respect sorted set ordering. · 9a914a63
      antirez authored
      When SORT is called with the option BY set to a string constant not
      inclduing the wildcard character "*", there is no way to sort the output
      so any ordering is valid. This allows the SORT internals to optimize its
      work and don't really sort the output at all.
      
      However it was odd that this option was not able to retain the natural
      order of a sorted set. This feature was requested by users multiple
      times as sometimes to call SORT with GET against sorted sets as a way to
      mass-fetch objects can be handy.
      
      This commit introduces two things:
      
      1) The ability of SORT to return sorted sets elements in their natural
      ordering when `BY nosort` is specified, accordingly to `DESC / ASC` options.
      2) The ability of SORT to optimize this case further if LIMIT is passed
      as well, avoiding to really fetch the whole sorted set, but directly
      obtaining the specified range.
      
      Because in this case the sorting is always deterministic, no
      post-sorting activity is performed when SORT is called from a Lua
      script.
      
      This commit fixes issue #98.
      9a914a63
  3. 01 Oct, 2012 1 commit
  4. 28 Sep, 2012 2 commits
    • antirez's avatar
      Scripting: add helper functions redis.error_reply() and redis.status_reply(). · 9c21b72b
      antirez authored
      A previous commit introduced Redis.NIL. This commit adds similar helper
      functions to return tables with a single field set to the specified
      string so that instead of using 'return {err="My Error"}' it is possible
      to use a more idiomatic form:
      
          return redis.error_reply("My Error")
          return redis.status_reply("OK")
      9c21b72b
    • antirez's avatar
      Scripting: redis.NIL to return nil bulk replies. · 6dd1693c
      antirez authored
      Lua arrays can't contain nil elements (see
      http://www.lua.org/pil/19.1.html for more information), so Lua scripts
      were not able to return a multi-bulk reply containing nil bulk
      elements inside.
      
      This commit introduces a special conversion: a table with just
      a "nilbulk" field set to a boolean value is converted by Redis as a nil
      bulk reply, but at the same time for Lua this type is not a "nil" so can
      be used inside Lua arrays.
      
      This type is also assigned to redis.NIL, so the following two forms
      are equivalent and will be able to return a nil bulk reply as second
      element of a three elements array:
      
          EVAL "return {1,redis.NIL,3}" 0
          EVAL "return {1,{nilbulk=true},3}" 0
      
      The result in redis-cli will be:
      
          1) (integer) 1
          2) (nil)
          3) (integer) 3
      6dd1693c
  5. 26 Sep, 2012 1 commit
  6. 21 Sep, 2012 3 commits
    • antirez's avatar
      Test for SRANDMEMBER with <count>. · 0ee3f055
      antirez authored
      0ee3f055
    • antirez's avatar
      SRANDMEMBER <count> leak fixed. · 578c9459
      antirez authored
      For "CASE 4" (see code) we need to free the element if it's already in
      the result dictionary and adding it failed.
      578c9459
    • antirez's avatar
      Added the SRANDMEMBER key <count> variant. · be90c803
      antirez authored
      SRANDMEMBER called with just the key argument can just return a single
      random element from a Redis Set. However many users need to return
      multiple unique elements from a Set, this is not a trivial problem to
      handle in the client side, and for truly good performance a C
      implementation was required.
      
      After many requests for this feature it was finally implemented.
      
      The problem implementing this command is the strategy to follow when
      the number of elements the user asks for is near to the number of
      elements that are already inside the set. In this case asking random
      elements to the dictionary API, and trying to add it to a temporary set,
      may result into an extremely poor performance, as most add operations
      will be wasted on duplicated elements.
      
      For this reason this implementation uses a different strategy in this
      case: the Set is copied, and random elements are returned to reach the
      specified count.
      
      The code actually uses 4 different algorithms optimized for the
      different cases.
      
      If the count is negative, the command changes behavior and allows for
      duplicated elements in the returned subset.
      be90c803
  7. 17 Sep, 2012 3 commits
    • antirez's avatar
      d310fbed
    • antirez's avatar
      b5b2acea
    • antirez's avatar
      A reimplementation of blocking operation internals. · 7eb850ef
      antirez authored
      Redis provides support for blocking operations such as BLPOP or BRPOP.
      This operations are identical to normal LPOP and RPOP operations as long
      as there are elements in the target list, but if the list is empty they
      block waiting for new data to arrive to the list.
      
      All the clients blocked waiting for th same list are served in a FIFO
      way, so the first that blocked is the first to be served when there is
      more data pushed by another client into the list.
      
      The previous implementation of blocking operations was conceived to
      serve clients in the context of push operations. For for instance:
      
      1) There is a client "A" blocked on list "foo".
      2) The client "B" performs `LPUSH foo somevalue`.
      3) The client "A" is served in the context of the "B" LPUSH,
      synchronously.
      
      Processing things in a synchronous way was useful as if "A" pushes a
      value that is served by "B", from the point of view of the database is a
      NOP (no operation) thing, that is, nothing is replicated, nothing is
      written in the AOF file, and so forth.
      
      However later we implemented two things:
      
      1) Variadic LPUSH that could add multiple values to a list in the
      context of a single call.
      2) BRPOPLPUSH that was a version of BRPOP that also provided a "PUSH"
      side effect when receiving data.
      
      This forced us to make the synchronous implementation more complex. If
      client "B" is waiting for data, and "A" pushes three elemnents in a
      single call, we needed to propagate an LPUSH with a missing argument
      in the AOF and replication link. We also needed to make sure to
      replicate the LPUSH side of BRPOPLPUSH, but only if in turn did not
      happened to serve another blocking client into another list ;)
      
      This were complex but with a few of mutually recursive functions
      everything worked as expected... until one day we introduced scripting
      in Redis.
      
      Scripting + synchronous blocking operations = Issue #614.
      
      Basically you can't "rewrite" a script to have just a partial effect on
      the replicas and AOF file if the script happened to serve a few blocked
      clients.
      
      The solution to all this problems, implemented by this commit, is to
      change the way we serve blocked clients. Instead of serving the blocked
      clients synchronously, in the context of the command performing the PUSH
      operation, it is now an asynchronous and iterative process:
      
      1) If a key that has clients blocked waiting for data is the subject of
      a list push operation, We simply mark keys as "ready" and put it into a
      queue.
      2) Every command pushing stuff on lists, as a variadic LPUSH, a script,
      or whatever it is, is replicated verbatim without any rewriting.
      3) Every time a Redis command, a MULTI/EXEC block, or a script,
      completed its execution, we run the list of keys ready to serve blocked
      clients (as more data arrived), and process this list serving the
      blocked clients.
      4) As a result of "3" maybe more keys are ready again for other clients
      (as a result of BRPOPLPUSH we may have push operations), so we iterate
      back to step "3" if it's needed.
      
      The new code has a much simpler semantics, and a simpler to understand
      implementation, with the disadvantage of not being able to "optmize out"
      a PUSH+BPOP as a No OP.
      
      This commit will be tested with care before the final merge, more tests
      will be added likely.
      7eb850ef
  8. 11 Sep, 2012 1 commit
    • antirez's avatar
      Make sure that SELECT argument is an integer or return an error. · bfc197c3
      antirez authored
      Unfortunately we had still the lame atoi() without any error checking in
      place, so "SELECT foo" would work as "SELECT 0". This was not an huge
      problem per se but some people expected that DB can be strings and not
      just numbers, and without errors you get the feeling that they can be
      numbers, but not the behavior.
      
      Now getLongFromObjectOrReply() is used as almost everybody else across
      the code, generating an error if the number is not an integer or
      overflows the long type.
      
      Thanks to @mipearson for reporting that on Twitter.
      bfc197c3
  9. 10 Sep, 2012 1 commit
  10. 05 Sep, 2012 3 commits
    • antirez's avatar
      BITCOUNT regression test for #582 fixed for 32 bit target. · 74e57d0e
      antirez authored
      Bug #582 was not present in 32 bit builds of Redis as
      getObjectFromLong() will return an error for overflow.
      
      This commit makes sure that the test does not fail because of the error
      returned when running against 32 bit builds.
      74e57d0e
    • Haruto Otake's avatar
      BITCOUNT: fix segmentation fault. · 749aac72
      Haruto Otake authored
      remove unsafe and unnecessary cast.
      until now, this cast may lead segmentation fault when end > UINT_MAX
      
      setbit foo 0 1
      bitcount  0 4294967295
      => ok
      bitcount  0 4294967296
      => cause segmentation fault.
      
      Note by @antirez: the commit was modified a bit to also change the
      string length type to long, since it's guaranteed to be at max 512 MB in
      size, so we can work with the same type across all the code path.
      
      A regression test was also added.
      749aac72
    • Salvatore Sanfilippo's avatar
      Merge pull request #576 from saj/fix-slave-ping-period · 24bc807b
      Salvatore Sanfilippo authored
      Bug fix: slaves being pinged every second
      24bc807b
  11. 04 Sep, 2012 3 commits
    • antirez's avatar
      Scripting: Force SORT BY constant determinism inside SORT itself. · 36741b2c
      antirez authored
      SORT is able to return (faster than when ordering) unordered output if
      the "BY" clause is used with a constant value. However we try to play
      well with scripting requirements of determinism providing always sorted
      outputs when SORT (and other similar commands) are called by Lua
      scripts.
      
      However we used the general mechanism in place in scripting in order to
      reorder SORT output, that is, if the command has the "S" flag set, the
      Lua scripting engine will take an additional step when converting a
      multi bulk reply to Lua value, calling a Lua sorting function.
      
      This is suboptimal as we can do it faster inside SORT itself.
      This is also broken as issue #545 shows us: basically when SORT is used
      with a constant BY, and additionally also GET is used, the Lua scripting
      engine was trying to order the output as a flat array, while it was
      actually a list of key-value pairs.
      
      What we do know is to recognized if the caller of SORT is the Lua client
      (since we can check this using the REDIS_LUA_CLIENT flag). If so, and if
      a "don't sort" condition is triggered by the BY option with a constant
      string, we force the lexicographical sorting.
      
      This commit fixes this bug and improves the performance, and at the same
      time simplifies the implementation. This does not mean I'm smart today,
      it means I was stupid when I committed the original implementation ;)
      36741b2c
    • antirez's avatar
      Sentinel: reply -IDONTKNOW to get-master-addr-by-name on lack of info. · 9bd0e097
      antirez authored
      If we don't have any clue about a master since it never replied to INFO
      so far, reply with an -IDONTKNOW error to SENTINEL
      get-master-addr-by-name requests.
      9bd0e097
    • antirez's avatar
      Sentinel: more easy master redirection if master is a slave. · 8bdde086
      antirez authored
      Before this commit Sentienl used to redirect master ip/addr if the
      current instance reported to be a slave only if this was the first INFO
      output received, and the role was found to be slave.
      
      Now instead also if we find that the runid is different, and the
      reported role is slave, we also redirect to the reported master ip/addr.
      
      This unifies the behavior of Sentinel in the case of a reboot (where it
      will see the first INFO output with the wrong role and will perform the
      redirection), with the behavior of Sentinel in the case of a change in
      what it sees in the INFO output of the master.
      8bdde086
  12. 02 Sep, 2012 1 commit
    • antirez's avatar
      Send an async PING before starting replication with master. · bb66fc31
      antirez authored
      During the first synchronization step of the replication process, a Redis
      slave connects with the master in a non blocking way. However once the
      connection is established the replication continues sending the REPLCONF
      command, and sometimes the AUTH command if needed. Those commands are
      send in a partially blocking way (blocking with timeout in the order of
      seconds).
      
      Because it is common for a blocked master to accept connections even if
      it is actually not able to reply to the slave requests, it was easy for
      a slave to block if the master had serious issues, but was still able to
      accept connections in the listening socket.
      
      For this reason we now send an asynchronous PING request just after the
      non blocking connection ended in a successful way, and wait for the
      reply before to continue with the replication process. It is very
      unlikely that a master replying to PING can't reply to the other
      commands.
      
      This solution was proposed by Didier Spezia (Thanks!) so that we don't
      need to turn all the replication process into a non blocking affair, but
      still the probability of a slave blocked is minimal even in the event of
      a failing master.
      
      Also we now use getsockopt(SO_ERROR) in order to check errors ASAP
      in the event handler, instead of waiting for actual I/O to return an
      error.
      
      This commit fixes issue #632.
      bb66fc31
  13. 31 Aug, 2012 2 commits
    • antirez's avatar
      Scripting: Reset Lua fake client reply_bytes after command execution. · e323635c
      antirez authored
      Lua scripting uses a fake client in order to run commands in the context
      of a client, accumulate the reply, and convert it into a Lua object
      to return to the caller. This client is reused again and again, and is
      referenced by the server.lua_client globally accessible pointer.
      
      However after every call to redis.call() or redis.pcall(), that is
      handled by the luaRedisGenericCommand() function, the reply_bytes field
      of the client was not set back to zero. This filed is used to estimate
      the amount of memory currently used in the reply. Because of the lack of
      reset, script after script executed, this value used to get bigger and
      bigger, and in the end on 32 bit systems it triggered the following
      assert:
      
          redisAssert(c->reply_bytes < ULONG_MAX-(1024*64));
      
      On 64 bit systems this does not happen because it takes too much time to
      reach values near to 2^64 for users to see the practical effect of the
      bug.
      
      Now in the cleanup stage of luaRedisGenericCommand() we reset the
      reply_bytes counter to zero, avoiding the issue. It is not practical to
      add a test for this bug, but the fix was manually tested using a
      debugger.
      
      This commit fixes issue #656.
      e323635c
    • antirez's avatar
      Scripting: require at least one argument for redis.call(). · 46c31a15
      antirez authored
      Redis used to crash with a call like the following:
      
          EVAL "redis.call()" 0
      
      Now the explicit check for at least one argument prevents the problem.
      
      This commit fixes issue #655.
      46c31a15
  14. 30 Aug, 2012 1 commit
  15. 29 Aug, 2012 2 commits
  16. 28 Aug, 2012 5 commits
    • antirez's avatar
    • antirez's avatar
      Sentinel: Sentinel-side support for slave priority. · 3ec701e0
      antirez authored
      The slave priority that is now published by Redis in INFO output is
      now used by Sentinel in order to select the slave with minimum priority
      for promotion, and in order to consider slaves with priority set to 0 as
      not able to play the role of master (they will never be promoted by
      Sentinel).
      
      The "slave-priority" field is now one of the fileds that Sentinel
      publishes when describing an instance via the SENTINEL commands such as
      "SENTINEL slaves mastername".
      3ec701e0
    • antirez's avatar
      Sentinel: Redis-side support for slave priority. · 169a44cb
      antirez authored
      A Redis slave can now be configured with a priority, that is an integer
      number that is shown in INFO output and can be get and set using the
      redis.conf file or the CONFIG GET/SET command.
      
      This field is used by Sentinel during slave election. A slave with lower
      priority is preferred. A slave with priority zero is never elected (and
      is considered to be impossible to elect even if it is the only slave
      available).
      
      A next commit will add support in the Sentinel side as well.
      169a44cb
    • antirez's avatar
      Sentinel: suppress harmless warning by initializing 'table' to NULL. · c14e0eca
      antirez authored
      Note that the assertion guarantees that one of the if branches setting
      table is always entered.
      c14e0eca
    • antirez's avatar
      Incrementally flush RDB on disk while loading it from a master. · 784b9308
      antirez authored
      This fixes issue #539.
      
      Basically if there is enough free memory the OS may buffer the RDB file
      that the slave transfers on disk from the master. The file may
      actually be flused on disk at once by the operating system when it gets
      closed by Redis, causing the close system call to block for a long time.
      
      This patch is a modified version of one provided by yoav-steinberg of
      @garantiadata (the original version was posted in the issue #539
      comments), and tries to flush the OS buffers incrementally (every 8 MB
      of loaded data).
      784b9308
  17. 24 Aug, 2012 4 commits
    • antirez's avatar
    • antirez's avatar
      Better Out of Memory handling. · 6fdc6354
      antirez authored
      The previous implementation of zmalloc.c was not able to handle out of
      memory in an application-specific way. It just logged an error on
      standard error, and aborted.
      
      The result was that in the case of an actual out of memory in Redis
      where malloc returned NULL (In Linux this actually happens under
      specific overcommit policy settings and/or with no or little swap
      configured) the error was not properly logged in the Redis log.
      
      This commit fixes this problem, fixing issue #509.
      Now the out of memory is properly reported in the Redis log and a stack
      trace is generated.
      
      The approach used is to provide a configurable out of memory handler
      to zmalloc (otherwise the default one logging the event on the
      standard output is used).
      6fdc6354
    • antirez's avatar
      Sentinel: send SCRIPT KILL on -BUSY reply and SDOWN instance. · 850789ce
      antirez authored
      From the point of view of Redis an instance replying -BUSY is down,
      since it is effectively not able to reply to user requests. However
      a looping script is a recoverable condition in Redis if the script still
      did not performed any write to the dataset. In that case performing a
      fail over is not optimal, so Sentinel now tries to restore the normal server
      condition killing the script with a SCRIPT KILL command.
      
      If the script already performed some write before entering an infinite
      (or long enough to timeout) loop, SCRIPT KILL will not work and the
      fail over will be triggered anyway.
      850789ce
    • antirez's avatar
      Sentinel: fixed a crash on script execution. · 01477753
      antirez authored
      The call to sentinelScheduleScriptExecution() lacked the final NULL
      argument to signal the end of arguments. This resulted into a crash.
      01477753
  18. 22 Aug, 2012 1 commit
  19. 21 Aug, 2012 2 commits
    • antirez's avatar
      redis-benchmark: disable big buffer cleanup in hiredis context. · 227b4293
      antirez authored
      This new hiredis features allows us to reuse a previous context reader
      buffer even if already very big in order to maximize performances with
      big payloads (Usually hiredis re-creates buffers when they are too big
      and unused in order to save memory).
      227b4293
    • antirez's avatar
      hiredis library updated. · d6704c9b
      antirez authored
      This version of hiredis merges modifications of the Redis fork with
      latest changes in the hiredis repository.
      
      The same version was pushed on the hiredis repository and will probably
      merged into the master branch in short time.
      d6704c9b
  20. 13 Aug, 2012 1 commit