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  1. Couchbase Server
  2. MB-48496

Fetch operator batch size never grows to pipeline cap

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Details

    • Bug
    • Status: Closed
    • Major
    • Resolution: Fixed
    • 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, 7.1.0, 7.0.1, 6.6.4
    • 7.1.0, 7.0.2, 6.6.5
    • query
    • Untriaged
    • 1
    • 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

          causes

          Bug - A problem which impairs or prevents the functions of the product. MB-49902 py-tpcc performance runs show regression in 7.0.2 build

          • Major - Major loss of function.
          • Closed
          relates to

          Bug - A problem which impairs or prevents the functions of the product. MB-48658 14 ms increase in latency for Flex Queries

          • Major - Major loss of function.
          • Closed
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          Activity

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            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

            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
            kamini.jagtiani Kamini Jagtiani added a comment -

            Chris Malarky Added the affected versions starting 5.5.0

            kamini.jagtiani Kamini Jagtiani added a comment - Chris Malarky  Added the affected versions starting 5.5.0
            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

            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
            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.

            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.
            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

            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
            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
            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

              pierre.regazzoni Pierre Regazzoni
              marco.greco Marco Greco
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              Dates

                Created:
                Updated:
                Resolved:

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