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  1. MariaDB Server
  2. MDEV-15914

performance regression for mass update

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      Updating a column in all rows of an InnoDB table has become slower in MariaDB 10.3, compared to 10.2. Test case

      drop table if exists t1;
      		 
      create table t1 (id serial, c1 int, c2 char(10) default 'foobar');
      		 
      insert into t1 (c1) values (rand()*1000);
      		 
      insert into t1 (c1) select rand()*1000 from t1;
      		 
      ... (19 more times)
      		 
      update t1 set c2='x';

      The final UPDATE touches 1 mio rows. There is no index involved. The update can be done in place. In 10.2.14 the updates takes 2 seconds on average, in 10.3.5 it takes 3 seconds on average. More numbers in related MDEV-15213.

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          relates to

          Task - A task that needs to be done. MDEV-14425 Change the InnoDB redo log format to reduce write amplification

          • Blocker - Blocks development and/or testing work, production could not run.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-16041 Do not write for null update (properly fix MySQL Bug#29157)

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-15213 UPDATEs are slow after instant ADD COLUMN

          • Major - Major loss of function.
          • Closed

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              marko Marko Mäkelä
              axel Axel Schwenke
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