Uploaded image for project: 'MariaDB Server'
  1. MariaDB Server
  2. MDEV-11825

Make session variables TRACKING enabled by default

Details

    • 10.2.4-1, 10.2.4-2

    Description

      Make by default tracking for:
      autocommit,
      Character_set_client,
      Character_set_connection,
      Character_set_results,
      time_zone

      Attachments

        Activity

          sanja Oleksandr Byelkin added a comment - - edited

          revision-id: 10c0278bc08f4e1b179dfcaae8fbfc4c4a0f51c1 (mariadb-10.2.3-76-g10c0278bc08)
          parent(s): 9ea0b44c5696d9357465625c3fc9b7f57a856009
          committer: Oleksandr Byelkin
          timestamp: 2017-01-18 10:40:17 +0100
          message:

          MDEV-11825: Make session variables TRACKING enabled by default

          sanja Oleksandr Byelkin added a comment - - edited revision-id: 10c0278bc08f4e1b179dfcaae8fbfc4c4a0f51c1 (mariadb-10.2.3-76-g10c0278bc08) parent(s): 9ea0b44c5696d9357465625c3fc9b7f57a856009 committer: Oleksandr Byelkin timestamp: 2017-01-18 10:40:17 +0100 message: MDEV-11825 : Make session variables TRACKING enabled by default —

          What's the effect on the performance?

          serg Sergei Golubchik added a comment - What's the effect on the performance?
          sanja Oleksandr Byelkin added a comment - - edited

          For query which do not change something (which most of the query) I do not see difference:
          I make 100000 SELECT 1 and result definitely do not depend on the variable set:
          without variables run: 6924 6483 6509 6731
          with the variable: 7001 6533 6283 6615

          test suite is (with first 2 lines interchangeable of course)

          SET session_track_system_variables="";
          SET session_track_system_variables="autocommit,character_set_client,character_set_connection,character_set_results,time_zone";
           
          --disable_query_log
          --disable_result_log
          let $1= 100000;
          while ($1)
          {
            SELECT 1;
            dec $1;
          }
          --enable_query_log
          --enable_result_log
          

          other extreme case when each execution leads to change:
          the same number of SET names:
          without variables run: 4739 4721 4744 4700
          with the variable: 5120 5340 4873 5124

          in this extreme case difference is 7.5% (but I do not think that it is real scenario)

          here is test suite for it:

          SET session_track_system_variables="";
          SET session_track_system_variables="autocommit,character_set_client,character_set_connection,character_set_results,time_zone";
           
          --disable_query_log
          --disable_result_log
          let $1= 50000;
          while ($1)
          {
            SET names utf8;
            SET names latin1;
            dec $1;
          }
          --enable_query_log
          --enable_result_log
          

          sanja Oleksandr Byelkin added a comment - - edited For query which do not change something (which most of the query) I do not see difference: I make 100000 SELECT 1 and result definitely do not depend on the variable set: without variables run: 6924 6483 6509 6731 with the variable: 7001 6533 6283 6615 test suite is (with first 2 lines interchangeable of course) SET session_track_system_variables= "" ; SET session_track_system_variables= "autocommit,character_set_client,character_set_connection,character_set_results,time_zone" ;   --disable_query_log --disable_result_log let $1= 100000; while ($1) { SELECT 1; dec $1; } --enable_query_log --enable_result_log other extreme case when each execution leads to change: the same number of SET names: without variables run: 4739 4721 4744 4700 with the variable: 5120 5340 4873 5124 in this extreme case difference is 7.5% (but I do not think that it is real scenario) here is test suite for it: SET session_track_system_variables= "" ; SET session_track_system_variables= "autocommit,character_set_client,character_set_connection,character_set_results,time_zone" ;   --disable_query_log --disable_result_log let $1= 50000; while ($1) { SET names utf8; SET names latin1; dec $1; } --enable_query_log --enable_result_log

          ok to push, then

          serg Sergei Golubchik added a comment - ok to push, then

          People

            sanja Oleksandr Byelkin
            sanja Oleksandr Byelkin
            Votes:
            0 Vote for this issue
            Watchers:
            2 Start watching this issue

            Dates

              Created:
              Updated:
              Resolved:

              Git Integration

                Error rendering 'com.xiplink.jira.git.jira_git_plugin:git-issue-webpanel'. Please contact your Jira administrators.