1. 24 May, 2012 1 commit
    • antirez's avatar
      Allow an AOF rewrite buffer > 2GB (Fix for issue #504). · edb95253
      antirez authored
      During the AOF rewrite process, the parent process needs to accumulate
      the new writes in an in-memory buffer: when the child will terminate the
      AOF rewriting process this buffer (that ist the difference between the
      dataset when the rewrite was started, and the current dataset) is
      flushed to the new AOF file.
      
      We used to implement this buffer using an sds.c string, but sds.c has a
      2GB limit. Sometimes the dataset can be big enough, the amount of writes
      so high, and the rewrite process slow enough that we overflow the 2GB
      limit, causing a crash, documented on github by issue #504.
      
      In order to prevent this from happening, this commit introduces a new
      system to accumulate writes, implemented by a linked list of blocks of
      10 MB each, so that we also avoid paying the reallocation cost.
      
      Note that theoretically modern operating systems may implement realloc()
      simply as a remaping of the old pages, thus with very good performances,
      see for instance the mremap() syscall on Linux. However this is not
      always true, and jemalloc by default avoids doing this because there are
      issues with the current implementation of mremap().
      
      For this reason we are using a linked list of blocks instead of a single
      block that gets reallocated again and again.
      
      The changes in this commit lacks testing, that will be performed before
      merging into the unstable branch. This fix will not enter 2.4 because it
      is too invasive. However 2.4 will log a warning when the AOF rewrite
      buffer is near to the 2GB limit.
      edb95253
  2. 14 May, 2012 3 commits
    • antirez's avatar
      activeExpireCycle(): better precision in max time used. · eee68054
      antirez authored
      activeExpireCycle() can consume no more than a few milliseconds per
      iteration. This commit improves the precision of the check for the time
      elapsed in two ways:
      
      1) We check every 16 iterations instead of the main loop instead of 256.
      2) We reset iterations at the start of the function and not every time
         we switch to the next database, so the check is correctly performed
         every 16 iterations.
      eee68054
    • antirez's avatar
      Impovements for: Redis timer, hashes rehashing, keys collection. · a8a981a8
      antirez authored
      A previous commit introduced REDIS_HZ define that changes the frequency
      of calls to the serverCron() Redis function. This commit improves
      different related things:
      
      1) Software watchdog: now the minimal period can be set according to
      REDIS_HZ. The minimal period is two times the timer period, that is:
      
          (1000/REDIS_HZ)*2 milliseconds
      
      2) The incremental rehashing is now performed in the expires dictionary
      as well.
      
      3) The activeExpireCycle() function was improved in different ways:
      
      - Now it checks if it already used too much time using microseconds
        instead of milliseconds for better precision.
      - The time limit is now calculated correctly, in the previous version
        the division was performed before of the multiplication resulting in
        a timelimit of 0 if HZ was big enough.
      - Databases with less than 1% of buckets fill in the hash table are
        skipped, because getting random keys is too expensive in this
        condition.
      
      4) tryResizeHashTables() is now called at every timer call, we need to
         match the number of calls we do to the expired keys colleciton cycle.
      
      5) REDIS_HZ was raised to 100.
      a8a981a8
    • antirez's avatar
      Redis timer interrupt frequency configurable as REDIS_HZ. · f7f2b261
      antirez authored
      Redis uses a function called serverCron() that is very similar to the
      timer interrupt of an operating system. This function is used to handle
      a number of asynchronous things, like active expired keys collection,
      clients timeouts, update of statistics, things related to the cluster
      and replication, triggering of BGSAVE and AOF rewrite process, and so
      forth.
      
      In the past the timer was called 1 time per second. At some point it was
      raised to 10 times per second, but it still was fixed and could not be
      changed even at compile time, because different functions called from
      serverCron() assumed a given fixed frequency.
      
      This commmit makes the frequency configurable, so that it is simpler to
      pick a good tradeoff between overhead of this function (that is usually
      very small) and the responsiveness of Redis during a few critical
      circumstances where a lot of work is done inside the timer.
      
      An example of such a critical condition is mass-expire of a lot of keys
      in the same second. Up to a given percentage of CPU time is used to
      perform expired keys collection per expire cylce. Now changing the
      REDIS_HZ macro it is possible to do less work but more times per second
      in order to block the server for less time.
      
      If this patch will work well in our tests it will enter Redis 2.6-final.
      f7f2b261
  3. 12 May, 2012 2 commits
    • antirez's avatar
    • antirez's avatar
      More incremental active expired keys collection process. · 3a401464
      antirez authored
      If a large amonut of keys are all expiring about at the same time, the
      "active" expired keys collection cycle used to block as far as the
      percentage of already expired keys was >= 25% of the total population of
      keys with an expire set.
      
      This could block the server even for many seconds in order to reclaim
      memory ASAP. The new algorithm uses at max a small amount of
      milliseconds per cycle, even if this means reclaiming the memory less
      promptly it also means a more responsive server.
      3a401464
  4. 02 May, 2012 1 commit
  5. 27 Apr, 2012 1 commit
    • antirez's avatar
      Don't use an alternative stack for SIGSEGV & co. · a28ab2a9
      antirez authored
      This commit reverts most of c5757662, in
      order to use back main stack for signal handling.
      
      The main reason is that otherwise it is completely pointless that we do
      a lot of efforts to print the stack trace on crash, and the content of
      the stack and registers as well. Using an alternate stack broken this
      feature completely.
      a28ab2a9
  6. 19 Apr, 2012 1 commit
  7. 18 Apr, 2012 1 commit
  8. 13 Apr, 2012 3 commits
  9. 10 Apr, 2012 2 commits
  10. 08 Apr, 2012 1 commit
  11. 06 Apr, 2012 1 commit
  12. 05 Apr, 2012 1 commit
  13. 04 Apr, 2012 4 commits
  14. 03 Apr, 2012 1 commit
  15. 30 Mar, 2012 1 commit
  16. 28 Mar, 2012 3 commits
  17. 27 Mar, 2012 1 commit
  18. 25 Mar, 2012 1 commit
    • antirez's avatar
      New INFO field aof_delayed_fsync introduced. · 81f32c7b
      antirez authored
      This new field counts all the times Redis is configured with AOF enabled and
      fsync policy 'everysec', but the previous fsync performed by the
      background thread was not able to complete within two seconds, forcing
      Redis to perform a write against the AOF file while the fsync is still
      in progress (likely a blocking operation).
      81f32c7b
  19. 24 Mar, 2012 1 commit
  20. 22 Mar, 2012 3 commits
    • antirez's avatar
      Correctly create shared.oomerr as an sds string. · 3f7ad833
      antirez authored
      3f7ad833
    • antirez's avatar
      DEBUG should not be flagged as w otherwise we can not call DEBUG DIGEST and... · 38bb4522
      antirez authored
      DEBUG should not be flagged as w otherwise we can not call DEBUG DIGEST and other commands against read only slaves.
      38bb4522
    • antirez's avatar
      Support for read-only slaves. Semantical fixes. · 05406168
      antirez authored
      This commit introduces support for read only slaves via redis.conf and CONFIG GET/SET commands. Also various semantical fixes are implemented here:
      
      1) MULTI/EXEC with only read commands now work where the server is into a state where writes (or commands increasing memory usage) are not allowed. Before this patch everything inside a transaction would fail in this conditions.
      
      2) Scripts just calling read-only commands will work against read only
      slaves, when the server is out of memory, or when persistence is into an
      error condition. Before the patch EVAL always failed in this condition.
      05406168
  21. 19 Mar, 2012 1 commit
  22. 18 Mar, 2012 3 commits
  23. 15 Mar, 2012 1 commit
    • antirez's avatar
      Fix for issue #391. · f1eaf572
      antirez authored
      Use a simple protocol between clientsCron() and helper functions to
      understand if the client is still valind and clientsCron() should
      continue processing or if the client was freed and we should continue
      with the next one.
      f1eaf572
  24. 14 Mar, 2012 2 commits