1. 17 Jul, 2018 1 commit
    • Oran Agra's avatar
      fix rare replication stream corruption with disk-based replication · d5559898
      Oran Agra authored
      The slave sends \n keepalive messages to the master while parsing the rdb,
      and later sends REPLCONF ACK once a second. rarely, the master recives both
      a linefeed char and a REPLCONF in the same read, \n*3\r\n$8\r\nREPLCONF\r\n...
      and it tries to trim two chars (\r\n) from the query buffer,
      trimming the '*' from *3\r\n$8\r\nREPLCONF\r\n...
      
      then the master tries to process a command starting with '3' and replies to
      the slave a bunch of -ERR and one +OK.
      although the slave silently ignores these (prints a log message), this corrupts
      the replication offset at the slave since the slave increases the replication
      offset, and the master did not.
      
      other than the fix in processInlineBuffer, i did several other improvments
      while hunting this very rare bug.
      
      - when redis replies with "unknown command" it includes a portion of the
        arguments, not just the command name. so it would be easier to understand
        what was recived, in my case, on the slave side,  it was -ERR, but
        the "arguments" were the interesting part (containing info on the error).
      - about a year ago i added code in addReplyErrorLength to print the error to
        the log in case of a reply to master (since this string isn't actually
        trasmitted to the master), now changed that block to print a similar log
        message to indicate an error being sent from the master to the slave.
        note that the slave is marked as CLIENT_SLAVE only after PSYNC was received,
        so this will not cause any harm for REPLCONF, and will only indicate problems
        that are gonna corrupt the replication stream anyway.
      - two places were c->reply was emptied, and i wanted to reset sentlen
        this is a precaution (i did not actually see such a problem), since a
        non-zero sentlen will cause corruption to be transmitted on the socket.
      d5559898
  2. 16 Jul, 2018 2 commits
    • antirez's avatar
      Hopefully improve commenting of #5126. · f9c84d6d
      antirez authored
      Reading the PR gave me the opportunity to better specify what the code
      was doing in places where I was not immediately sure about what was
      going on. Moreover I documented the structure in server.h so that people
      reading the header file will immediately understand what the structure
      is useful for.
      f9c84d6d
    • Oran Agra's avatar
      slave buffers were wasteful and incorrectly counted causing eviction · bf680b6f
      Oran Agra authored
      A) slave buffers didn't count internal fragmentation and sds unused space,
         this caused them to induce eviction although we didn't mean for it.
      
      B) slave buffers were consuming about twice the memory of what they actually needed.
      - this was mainly due to sdsMakeRoomFor growing to twice as much as needed each time
        but networking.c not storing more than 16k (partially fixed recently in 237a38737).
      - besides it wasn't able to store half of the new string into one buffer and the
        other half into the next (so the above mentioned fix helped mainly for small items).
      - lastly, the sds buffers had up to 30% internal fragmentation that was wasted,
        consumed but not used.
      
      C) inefficient performance due to starting from a small string and reallocing many times.
      
      what i changed:
      - creating dedicated buffers for reply list, counting their size with zmalloc_size
      - when creating a new reply node from, preallocate it to at least 16k.
      - when appending a new reply to the buffer, first fill all the unused space of the
        previous node before starting a new one.
      
      other changes:
      - expose mem_not_counted_for_evict info field for the benefit of the test suite
      - add a test to make sure slave buffers are counted correctly and that they don't cause eviction
      bf680b6f
  3. 09 Jul, 2018 3 commits
  4. 02 Jul, 2018 1 commit
  5. 29 Jun, 2018 1 commit
  6. 28 Jun, 2018 2 commits
  7. 27 Jun, 2018 6 commits
  8. 13 Jun, 2018 1 commit
  9. 07 Jun, 2018 1 commit
  10. 22 Mar, 2018 2 commits
  11. 15 Mar, 2018 2 commits
  12. 28 Feb, 2018 1 commit
  13. 27 Feb, 2018 1 commit
    • 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
  14. 13 Feb, 2018 1 commit
  15. 18 Jan, 2018 1 commit
    • Guy Benoish's avatar
      Replication buffer fills up on high rate traffic. · fd8efb7c
      Guy Benoish authored
      When feeding the master with a high rate traffic the the slave's feed is much slower.
      This causes the replication buffer to grow (indefinitely) which leads to slave disconnection.
      The problem is that writeToClient() decides to stop writing after NET_MAX_WRITES_PER_EVENT
      writes (In order to be fair to clients).
      We should ignore this when the client is a slave.
      It's better if clients wait longer, the alternative is that the slave has no chance to stay in
      sync in this situation.
      fd8efb7c
  16. 11 Jan, 2018 1 commit
  17. 29 Dec, 2017 2 commits
  18. 06 Dec, 2017 1 commit
    • antirez's avatar
      Change indentation and other minor details of PR #4489. · 522760fa
      antirez authored
      The main change introduced by this commit is pretending that help
      arrays are more text than code, thus indenting them at level 0. This
      improves readability, and is an old practice when defining arrays of
      C strings describing text.
      
      Additionally a few useless return statements are removed, and the HELP
      subcommand capitalized when printed to the user.
      522760fa
  19. 05 Dec, 2017 3 commits
  20. 03 Dec, 2017 1 commit
  21. 01 Dec, 2017 2 commits
  22. 30 Nov, 2017 1 commit
  23. 28 Nov, 2017 1 commit
    • Itamar Haber's avatar
      Standardizes the 'help' subcommand · 59d52f7f
      Itamar Haber authored
      This adds a new `addReplyHelp` helper that's used by commands
      when returning a help text. The following commands have been
      touched: DEBUG, OBJECT, COMMAND, PUBSUB, SCRIPT and SLOWLOG.
      
      WIP
      
      Fix entry command table entry for OBJECT for HELP option.
      
      After #4472 the command may have just 2 arguments.
      
      Improve OBJECT HELP descriptions.
      
      See #4472.
      
      WIP 2
      
      WIP 3
      59d52f7f
  24. 11 Jul, 2017 1 commit
  25. 05 Jul, 2017 1 commit