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  1. Couchbase Server
  2. MB-6628

Seeing incorrect cache-miss-ratio ( very large ranging upto 500) during bidirectional XDCR.

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Critical
    • Resolution: Fixed
    • Affects Version/s: 2.0-beta-2
    • Fix Version/s: 2.0-beta-2
    • Component/s: couchbase-bucket, XDCR
    • Security Level: Public
    • Labels:
      None
    • Environment:
      2.0-1717
      Centos
      1024 vbuckets

      Description

      Load 1M and 1M items on 2 clusters.
      Setup a 2:2 bidirectional replication.
      Start mutations on the cluster1 and cluster2.

      Noticing a very large cache-miss-ratio on one of the clusters. = (ep_bg_fetch/ cmd_get)

      Here ep_bg_fetch contains bg_fetches from xdcr also and is much larger. This needs to be correctly reflected on the stats.

      ketaki@ubu-1512:~$ /opt/couchbase/bin/cbstats 10.3.121.31:11210 all | egrep "cmd_get|ep_bg|get_meta"
      cmd_get: 14816
      ep_bg_fetch_delay: 0
      ep_bg_fetched: 371532
      ep_bg_load: 76857782
      ep_bg_load_avg: 206
      ep_bg_max_load: 238681
      ep_bg_max_wait: 202492
      ep_bg_min_load: 0
      ep_bg_min_wait: 0
      ep_bg_num_samples: 371532
      ep_bg_remaining_jobs: 0
      ep_bg_wait: 108839514
      ep_bg_wait_avg: 292
      ep_num_ops_get_meta: 1575784
      ketaki@ubu-1512:~$ /opt/couchbase/bin/cbstats 10.3.121.31:11210 all | egrep "cmd_get|ep_bg|get_meta"
      cmd_get: 14892
      ep_bg_fetch_delay: 0
      ep_bg_fetched: 371592
      ep_bg_load: 76875865
      ep_bg_load_avg: 206
      ep_bg_max_load: 238681
      ep_bg_max_wait: 202492
      ep_bg_min_load: 0
      ep_bg_min_wait: 0
      ep_bg_num_samples: 371592
      ep_bg_remaining_jobs: 0
      ep_bg_wait: 108853566
      ep_bg_wait_avg: 292
      ep_num_ops_get_meta: 1576593
      ketaki@ubu-1512:~$

      Please let me know if you need additional information.

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        Activity

        Hide
        chiyoung Chiyoung Seo added a comment -

        Mike,

        This is a bug in ep-engine. We should not increment "ep_bg_fetched" for GET_META background fetches. We may need to add a separate stat for GET_META bg fetches.

        Show
        chiyoung Chiyoung Seo added a comment - Mike, This is a bug in ep-engine. We should not increment "ep_bg_fetched" for GET_META background fetches. We may need to add a separate stat for GET_META bg fetches.
        Show
        chiyoung Chiyoung Seo added a comment - http://review.couchbase.org/#/c/20896/
        Hide
        thuan Thuan Nguyen added a comment -

        Integrated in github-ep-engine-2-0 #432 (See http://qa.hq.northscale.net/job/github-ep-engine-2-0/432/)
        MB-6628: Seperate meta data bg fetch stats from bg fetch stats. (Revision f0352955cd4f2b60352d1ba6bac0d44446b8882f)

        Result = SUCCESS
        Mike Wiederhold :
        Files :

        • tests/ep_testsuite.cc
        • src/ep.cc
        • src/ep_engine.cc
        • src/stats.hh
        • docs/stats.org
        Show
        thuan Thuan Nguyen added a comment - Integrated in github-ep-engine-2-0 #432 (See http://qa.hq.northscale.net/job/github-ep-engine-2-0/432/ ) MB-6628 : Seperate meta data bg fetch stats from bg fetch stats. (Revision f0352955cd4f2b60352d1ba6bac0d44446b8882f) Result = SUCCESS Mike Wiederhold : Files : tests/ep_testsuite.cc src/ep.cc src/ep_engine.cc src/stats.hh docs/stats.org

          People

          • Assignee:
            mikew Mike Wiederhold
            Reporter:
            ketaki Ketaki Gangal
          • Votes:
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            Watchers:
            1 Start watching this issue

            Dates

            • Created:
              Updated:
              Resolved:

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