Uploaded image for project: 'Couchbase Server'
  1. Couchbase Server
  2. MB-48496

Fetch operator batch size never grows to pipeline cap

    XMLWordPrintable

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 6.5.0, 6.0.0, 5.5.0, 5.5.1, 5.5.2, 5.5.3, 6.0.1, 6.0.2, 5.5.4, 6.0.3, 5.5.5, 5.5.6, 6.0.4, 6.5.1, 6.0.5, 6.6.0, 6.6.1, 6.6.2, 6.5.2, 7.0.0, 6.6.3, Neo, 7.0.1
    • Fix Version/s: Neo, 7.0.2, 6.6.4
    • Component/s: query
    • Triage:
      Untriaged
    • Story Points:
      1
    • Is this a Regression?:
      Yes

      Description

      In mad hatter and later, if the amount of data to be fetched exceeds the current pipeline cap, this latter is not increased to match the value exchange capacity, which results in a lower throughput.

        Attachments

          Issue Links

          No reviews matched the request. Check your Options in the drop-down menu of this sections header.

            Activity

            Hide
            build-team Couchbase Build Team added a comment -

            Build couchbase-server-7.1.0-1304 contains query commit 66a4003 with commit message:
            MB-48496 grow fetch batch to pipeline cap

            Show
            build-team Couchbase Build Team added a comment - Build couchbase-server-7.1.0-1304 contains query commit 66a4003 with commit message: MB-48496 grow fetch batch to pipeline cap
            Hide
            kamini.jagtiani Kamini Jagtiani added a comment -

            Chris Malarky Added the affected versions starting 5.5.0

            Show
            kamini.jagtiani Kamini Jagtiani added a comment - Chris Malarky  Added the affected versions starting 5.5.0
            Hide
            build-team Couchbase Build Team added a comment -

            Build couchbase-server-7.0.2-6683 contains query commit 7e15991 with commit message:
            MB-48496 grow fetch batch to pipeline cap

            Show
            build-team Couchbase Build Team added a comment - Build couchbase-server-7.0.2-6683 contains query commit 7e15991 with commit message: MB-48496 grow fetch batch to pipeline cap
            Hide
            marco.greco Marco Greco added a comment -

            Repro:

            1) Install travel-sample
            2) INSERT INTO `travel-sample` (KEY UUID(), VALUE t) SELECT t FROM `travel-sample` t;
            3) INSERT INTO `travel-sample` (KEY UUID(), VALUE t) SELECT t FROM `travel-sample` t;
            4) At this time you have 126364 documents
            5) SELECT COUNT(1) FROM `travel-sample` t WHERE t.x IS MISSING;

            without the fix the select is much slower than with the fix (anything in between 30% and 100%)

            As an alternative without the fix, setting pipeline_cap to 512 improves the performance, with the fix pipeline_cap makes no difference.

            Show
            marco.greco Marco Greco added a comment - Repro: 1) Install travel-sample 2) INSERT INTO `travel-sample` (KEY UUID(), VALUE t) SELECT t FROM `travel-sample` t; 3) INSERT INTO `travel-sample` (KEY UUID(), VALUE t) SELECT t FROM `travel-sample` t; 4) At this time you have 126364 documents 5) SELECT COUNT(1) FROM `travel-sample` t WHERE t.x IS MISSING; without the fix the select is much slower than with the fix (anything in between 30% and 100%) As an alternative without the fix, setting pipeline_cap to 512 improves the performance, with the fix pipeline_cap makes no difference.
            Hide
            build-team Couchbase Build Team added a comment -

            Build couchbase-server-6.6.4-9918 contains query commit d83a62e with commit message:
            MB-48496 grow fetch batch to pipeline cap

            Show
            build-team Couchbase Build Team added a comment - Build couchbase-server-6.6.4-9918 contains query commit d83a62e with commit message: MB-48496 grow fetch batch to pipeline cap
            Hide
            pierre.regazzoni Pierre Regazzoni added a comment -

            Verfied on 7.1.0-1304, 7.0.2-6683 and 6.6.4-9918.

            Ran repro and see following perf difference with fix vs without fix respectively:

            • for 7.1.0 and 7.0.2: 14s vs 24s
            • for 6.6.4: 20s vs 31s
            Show
            pierre.regazzoni Pierre Regazzoni added a comment - Verfied on 7.1.0-1304, 7.0.2-6683 and 6.6.4-9918. Ran repro and see following perf difference with fix vs without fix respectively: for 7.1.0 and 7.0.2: 14s vs 24s for 6.6.4: 20s vs 31s

              People

              Assignee:
              pierre.regazzoni Pierre Regazzoni
              Reporter:
              marco.greco Marco Greco
              Votes:
              0 Vote for this issue
              Watchers:
              7 Start watching this issue

                Dates

                Created:
                Updated:
                Resolved:

                  Gerrit Reviews

                  There are no open Gerrit changes

                    PagerDuty