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  1. Core Server
  2. SERVER-9320

Several connections request to split a same chunk at the same time.

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major - P3
    • Resolution: Works as Designed
    • Affects Version/s: 2.2.3
    • Fix Version/s: None
    • Component/s: Performance, Sharding
    • Labels:
      None
    • Environment:
      Linux 2.6.38-2-amd64
      90 mongos linked to one cluster with 4 shards.
    • Operating System:
      Linux

      Description

      Hi,
      By looking into the log, I found that several connections will request to split a same chunk a the same time, which may affect the performance.

      log:

       
      Tue Apr  9 09:48:45 [conn57348] request split points lookup for chunk tw2_log_10191.gm_quest { : 387362153 } -->> { : 403798381 }
      Tue Apr  9 09:48:45 [conn57347] request split points lookup for chunk tw2_log_10191.gm_quest { : 387362153 } -->> { : 403798381 }
      Tue Apr  9 09:48:45 [conn57646] request split points lookup for chunk tw2_log_10191.gm_quest { : 387362153 } -->> { : 403798381 }
      Tue Apr  9 09:48:45 [conn57648] request split points lookup for chunk tw2_log_10191.gm_quest { : 387362153 } -->> { : 403798381 }
      Tue Apr  9 09:48:45 [conn57647] request split points lookup for chunk tw2_log_10191.gm_quest { : 387362153 } -->> { : 403798381 }
      Tue Apr  9 09:48:46 [conn57348] warning: Finding the split vector for tw2_log_10191.gm_quest over { _sk: 1 } keyCount: 203360 numSplits: 1 lookedAt: 61189 took 1246ms
      Tue Apr  9 09:48:46 [conn57348] command admin.$cmd command: { splitVector: "tw2_log_10191.gm_quest", keyPattern: { _sk: 1 }, min: { _sk: 387362153 }, max: { _sk: 403798381 }, maxChunkSizeBytes: 67108864, maxSplitPoints: 2, maxChunkObjects: 250000, $auth: { local: { __system: 2 } } } ntoreturn:1 keyUpdates:0 numYields: 301 locks(micros) r:2263610 reslen:70 1247ms
      Tue Apr  9 09:48:46 [conn57647] warning: Finding the split vector for tw2_log_10191.gm_quest over { _sk: 1 } keyCount: 203360 numSplits: 1 lookedAt: 61191 took 1085ms
      Tue Apr  9 09:48:46 [conn57647] command admin.$cmd command: { splitVector: "tw2_log_10191.gm_quest", keyPattern: { _sk: 1 }, min: { _sk: 387362153 }, max: { _sk: 403798381 }, maxChunkSizeBytes: 67108864, maxSplitPoints: 2, maxChunkObjects: 250000, $auth: { local: { __system: 2 } } } ntoreturn:1 keyUpdates:0 numYields: 32 locks(micros) r:2150012 reslen:70 1085ms
      Tue Apr  9 09:48:46 [conn57646] warning: Finding the split vector for tw2_log_10191.gm_quest over { _sk: 1 } keyCount: 203360 numSplits: 1 lookedAt: 61193 took 1109ms
      Tue Apr  9 09:48:46 [conn57646] command admin.$cmd command: { splitVector: "tw2_log_10191.gm_quest", keyPattern: { _sk: 1 }, min: { _sk: 387362153 }, max: { _sk: 403798381 }, maxChunkSizeBytes: 67108864, maxSplitPoints: 2, maxChunkObjects: 250000, $auth: { local: { __system: 2 } } } ntoreturn:1 keyUpdates:0 numYields: 33 locks(micros) r:2188370 reslen:70 1109ms
      Tue Apr  9 09:48:46 [conn57648] warning: Finding the split vector for tw2_log_10191.gm_quest over { _sk: 1 } keyCount: 203360 numSplits: 1 lookedAt: 61196 took 1118ms
      Tue Apr  9 09:48:46 [conn57648] command admin.$cmd command: { splitVector: "tw2_log_10191.gm_quest", keyPattern: { _sk: 1 }, min: { _sk: 387362153 }, max: { _sk: 403798381 }, maxChunkSizeBytes: 67108864, maxSplitPoints: 2, maxChunkObjects: 250000, $auth: { local: { __system: 2 } } } ntoreturn:1 keyUpdates:0 numYields: 22 locks(micros) r:2220804 reslen:70 1118ms
      Tue Apr  9 09:48:46 [conn57347] warning: Finding the split vector for tw2_log_10191.gm_quest over { _sk: 1 } keyCount: 203360 numSplits: 1 lookedAt: 61202 took 1138ms
      Tue Apr  9 09:48:46 [conn57347] command admin.$cmd command: { splitVector: "tw2_log_10191.gm_quest", keyPattern: { _sk: 1 }, min: { _sk: 387362153 }, max: { _sk: 403798381 }, maxChunkSizeBytes: 67108864, maxSplitPoints: 2, maxChunkObjects: 250000, $auth: { local: { __system: 2 } } } ntoreturn:1 keyUpdates:0 numYields: 102 locks(micros) r:2260997 reslen:70 1138ms

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              Assignee:
              Unassigned
              Reporter:
              strlee stronglee
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                Updated:
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