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  1. MariaDB Server
  2. MDEV-31589

Secondary index MVCC access is unnecessarily inefficient

Details

    • Bug
    • Status: Stalled (View Workflow)
    • Critical
    • Resolution: Unresolved
    • 10.4(EOL), 10.5, 10.6, 10.7(EOL), 10.8(EOL), 10.9(EOL), 10.10(EOL), 10.11, 11.0(EOL), 11.1(EOL), 11.2(EOL)
    • 10.6, 10.11
    • Storage Engine - InnoDB

    Description

      As noted in MDEV-31558, a covering secondary index read in InnoDB would look up the clustered index record twice and retrieve the matching version. In the test innodb.mvcc_secondary we have a table with 2 versions of 1 row, and the first SELECT statement would construct the old version of the clustered index not once, but twice.

      MDEV-20301 replaced row_sel_get_clust_rec_for_mysql() with Row_sel_get_clust_rec_for_mysql::operator(), which adds some caching. It missed an opportunity to remove the call row_sel_sec_rec_is_for_clust_rec() and to perform those checks as part of the loop that invokes row_sel_build_prev_vers_for_mysql().

      Attachments

        Issue Links

          relates to

          Bug - A problem which impairs or prevents the functions of the product. MDEV-32286 ANALYZE displays a huge number of InnoDB secondary index pages_accessed

          • Critical - Crashes, loss of data, severe memory leak.
          • Confirmed

          New Feature - A new feature of the product, which has yet to be developed. MDEV-17598 InnoDB index option for per-record transaction ID

          • Major - Major loss of function.
          • Open

          Bug - A problem which impairs or prevents the functions of the product. MDEV-20301 InnoDB's MVCC has O(N^2) behaviors

          • Major - Major loss of function.
          • Closed

          Task - A task that needs to be done. MDEV-31558 Add InnoDB engine information to the slow query log

          • Critical - Crashes, loss of data, severe memory leak.
          • Closed

          Activity

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            marko Marko Mäkelä created issue -
            marko Marko Mäkelä made changes -
            Field Original Value New Value
            marko Marko Mäkelä made changes -
            marko Marko Mäkelä made changes -
            marko Marko Mäkelä made changes -
            Status Open [ 1 ] Confirmed [ 10101 ]
            vlad.lesin Vladislav Lesin made changes -
            Priority Major [ 3 ] Critical [ 2 ]
            vlad.lesin Vladislav Lesin made changes -
            Status Confirmed [ 10101 ] In Progress [ 3 ]
            marko Marko Mäkelä made changes -
            julien.fritsch Julien Fritsch made changes -
            Fix Version/s 10.9 [ 26905 ]
            julien.fritsch Julien Fritsch made changes -
            Fix Version/s 10.10 [ 27530 ]
            JIraAutomate JiraAutomate made changes -
            Status In Progress [ 3 ] Stalled [ 10000 ]
            julien.fritsch Julien Fritsch made changes -
            Fix Version/s 11.0 [ 28320 ]
            julien.fritsch Julien Fritsch made changes -
            Fix Version/s 11.1 [ 28549 ]
            julien.fritsch Julien Fritsch made changes -
            Fix Version/s 11.2(EOL) [ 28603 ]

            People

              vlad.lesin Vladislav Lesin
              marko Marko Mäkelä
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              Dates

                Created:
                Updated:

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