Uploaded image for project: 'MariaDB Server'
  1. MariaDB Server
  2. MDEV-7620

Transaction lock wait is missing number of lock waits

Details

    Description

      Customer request. Currently, innodb transaction lock information does not contain any information how long/how many times transaction has waited a row/table lock.

      Attachments

        Activity

          revno: 4616
          committer: Jan Lindström <jplindst@mariadb.org>
          branch nick: 10.0-innodb
          timestamp: Mon 2015-02-23 11:24:19 +0200
          message:
          MDEV-7620: Transaction lock wait is missing number of lock
          waits and total wait time.

          jplindst Jan Lindström (Inactive) added a comment - revno: 4616 committer: Jan Lindström <jplindst@mariadb.org> branch nick: 10.0-innodb timestamp: Mon 2015-02-23 11:24:19 +0200 message: MDEV-7620 : Transaction lock wait is missing number of lock waits and total wait time.

          It turns out that this change was effectively reverted in MariaDB 10.2.2 when the InnoDB changes from MySQL 5.7.9 and 5.7.14 were applied. We still reserve two machine words related to this in each trx_t, but those data members are not being read or written anywhere.

          A proper implementation of this should expose the data via PERFORMANCE_SCHEMA and include some tests.

          marko Marko Mäkelä added a comment - It turns out that this change was effectively reverted in MariaDB 10.2.2 when the InnoDB changes from MySQL 5.7.9 and 5.7.14 were applied. We still reserve two machine words related to this in each trx_t , but those data members are not being read or written anywhere. A proper implementation of this should expose the data via PERFORMANCE_SCHEMA and include some tests.

          I removed the unused data structures in order to reduce the memory footprint in future 10.2 and later releases.

          If this feature is considered useful, it should be designed and implemented properly. InnoDB transaction data is being exported via confusingly named views in INFORMATION_SCHEMA. Logically, properties of individual transactions should be made available via PERFORMANCE_SCHEMA. It looks like MariaDB 10.0 and 10.1 exported the information only via SHOW ENGINE INNODB STATUS.

          marko Marko Mäkelä added a comment - I removed the unused data structures in order to reduce the memory footprint in future 10.2 and later releases. If this feature is considered useful, it should be designed and implemented properly. InnoDB transaction data is being exported via confusingly named views in INFORMATION_SCHEMA . Logically, properties of individual transactions should be made available via PERFORMANCE_SCHEMA . It looks like MariaDB 10.0 and 10.1 exported the information only via SHOW ENGINE INNODB STATUS .

          People

            jplindst Jan Lindström (Inactive)
            jplindst Jan Lindström (Inactive)
            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.