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  1. MariaDB Server
  2. MDEV-20199

RocksDB ROW_COUNT() after UPDATE always 1, even if the data has not changed.

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    Description

      In MariaDB 10.3.16 on ROCKSDB engine ROW_COUNT() return always 1 (not 0), after UPDETE, when data not changed.
      In InnoDB always returns 0 if the data has not changed.

      DROP TABLE IF EXISTS `test`;
      		 
       
      		 
      CREATE TABLE `test`
      		 
      (
      		 
      	`id` INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
      		 
      	`status` TINYINT UNSIGNED NOT NULL,
      		 
      	KEY(`status`)
      		 
      )
      		 
      ENGINE=ROCKSDB CHARACTER SET utf8 COLLATE utf8_general_ci;
      		 
       
      		 
      INSERT INTO `test`(`id`,`status`) VALUES (1,1),(2,2),(3,3);
      		 
       
      		 
      UPDATE `test` SET `status`=2 WHERE `id`=2;
      		 
       
      		 
      SELECT ROW_COUNT();

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          alice Alice Sherepa added a comment -

          Thanks for the report! Repeatable on 10.2-10.4:

          --source include/have_rocksdb.inc
          		 
          create table t1 ( id int , status int) engine=rocksdb;
          		 
          insert into t1(id,status) values (1,1),(2,2),(2,2),(2,2);
          		 
          update t1 set status=2 where id=2;
          		 
          select row_count();
          		 
           
          		 
          alter table t1 engine=myisam;
          		 
          update t1 set status=2 where id=2;
          		 
          select row_count();
          		 
          drop table t1;


          update t1 set status=2 where id=2;
          		 
          select row_count();
          		 
          row_count()
          		 
          3
          		 
          alter table t1 engine=myisam;
          		 
          update t1 set status=2 where id=2;
          		 
          select row_count();
          		 
          row_count()
          		 
          0

          alice Alice Sherepa added a comment - Thanks for the report! Repeatable on 10.2-10.4: --source include/have_rocksdb.inc create table t1 ( id int , status int ) engine=rocksdb; insert into t1(id,status) values (1,1),(2,2),(2,2),(2,2); update t1 set status=2 where id=2; select row_count();   alter table t1 engine=myisam; update t1 set status=2 where id=2; select row_count(); drop table t1; update t1 set status=2 where id=2; select row_count(); row_count() 3 alter table t1 engine=myisam; update t1 set status=2 where id=2; select row_count(); row_count() 0
          ilya Илья Индиго added a comment -

          Hello!
          If there is any progress in this bug?
          Can we expect its elimination in 10.5?
          Is this the original problem of the MyRocks engine itself, or is it a flaw in MariaDB?

          ilya Илья Индиго added a comment - Hello! If there is any progress in this bug? Can we expect its elimination in 10.5? Is this the original problem of the MyRocks engine itself, or is it a flaw in MariaDB?

          People

            psergei Sergei Petrunia
            ilya Илья Индиго
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              Created:
              Updated:

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