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  1. MariaDB Server
  2. MDEV-33913

TABLE_STATISTICS increments ROWS_CHANGED twice upon UPDATE and does not count DELETE

Details

    Description

      This is a regression introduced by MDEV-33151.
      The column rows_changed already existed, it wasn't added by MDEV-33151; but it now shows wrong counts for UPDATE/DELETE, which wasn't happening before, apparently due to the typo:

      @@ -40,14 +47,22 @@ static int table_stats_fill(THD *thd, TABLE_LIST *tables, COND *cond)
      		 
               check_grant(thd, SELECT_ACL, &tmp_table, 1, 1, 1))
      		 
             continue;
      		 
       
      +    rows_changed= (rows_stats->inserted + rows_stats->updated +
      		 
      +                   rows_stats->updated);


      set @userstat.save= @@userstat;
      		 
      set global userstat= 1;
      		 
       
      		 
      create table t (a int);
      		 
      insert into t values (1),(2);
      		 
       
      		 
      flush table_statistics;
      		 
      update t set a = a + 10;
      		 
      select rows_changed from information_schema.table_statistics where table_name = 't';
      		 
      delete from t where a = 11;
      		 
      select rows_changed from information_schema.table_statistics where table_name = 't';
      		 
       
      		 
      # Cleanup
      		 
      drop table t;
      		 
      set global userstat= @userstat.save;

      bb-11.5-MDEV-33151-userstat 36c7a912bc

      		 
      flush table_statistics;
      		 
      update t set a = a + 10;
      		 
      select rows_changed from information_schema.table_statistics where table_name = 't';
      		 
      rows_changed
      		 
      4
      		 
      delete from t where a = 11;
      		 
      select rows_changed from information_schema.table_statistics where table_name = 't';
      		 
      rows_changed
      		 
      4

      The expected result is "2" and "3" correspondingly, which is returned by the baseline.

      Attachments

        Issue Links

          is caused by

          New Feature - A new feature of the product, which has yet to be developed. MDEV-33151 Add more columns to TABLE_STATISTICS and USER STATS

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

          Activity

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            elenst Elena Stepanova added a comment -

            The only existing test which does UPDATE and DELETE in userstat context and thus could have caught the regression, main.information_schema_stats, unfortunately does UPDATE and DELETE in succession (without checking the counts in between), each touching exactly 1 row, so the error cancels out, and the end result remains the same as it was.

            elenst Elena Stepanova added a comment - The only existing test which does UPDATE and DELETE in userstat context and thus could have caught the regression, main.information_schema_stats , unfortunately does UPDATE and DELETE in succession (without checking the counts in between), each touching exactly 1 row, so the error cancels out, and the end result remains the same as it was.
            elenst Elena Stepanova added a comment -

            A tentative fix in bb-11.5-MDEV-33151-userstat:
            https://github.com/MariaDB/server/commit/fc9383808d51677dcf0e100195bb52615ce6ec2e

            elenst Elena Stepanova added a comment - A tentative fix in bb-11.5- MDEV-33151 -userstat: https://github.com/MariaDB/server/commit/fc9383808d51677dcf0e100195bb52615ce6ec2e
            monty Michael Widenius added a comment -

            Pushed fix to bb-11.5-monty

            monty Michael Widenius added a comment - Pushed fix to bb-11.5-monty

            People

              monty Michael Widenius
              elenst Elena Stepanova
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              Dates

                Created:
                Updated:
                Resolved:

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