Do a periodical commit in a large update query

Question

I'm newbie with pl/sql and i need to do a large update in my database. More than 4 million entries must be changed and i want to execute a commit after every 5.000 update. I'm pretty lost to do this.

Here my query.

update accounts a set a.validateid = 'TH20381', flagexport = 25, exportname ='zde'
where a.accountnumber >= 35026879 and a.ownerid like 'V35%';

Thanks in advance.

Answer 1

If you really need to do that, you can consider using DBMS_PARALLEL_EXECUTE package. Here is an example how it would look like:

DECLARE
  v_sql VARCHAR2(4000);
BEGIN
  -- create the task
  DBMS_PARALLEL_EXECUTE.create_task (task_name => 'update_accounts_task');

  -- define how the task should be split
  DBMS_PARALLEL_EXECUTE.create_chunks_by_rowid(task_name   => 'update_accounts_task',
                                               table_owner => 'YOUR_USERNAME',
                                               table_name  => 'ACCOUNTS',
                                               by_row      => true,
                                               chunk_size  => 5000);

  -- command to be split and executed - notice the condition on rowid
  -- which is required since we defined above that the task should be split
  -- by rowid
  v_sql   := 'UPDATE accounts
                 SET validateid = ''TH20381'',
                     flagexport = 25,
                     exportname = ''zde''
               WHERE accountnumber >= 35026879
                 AND ownerid LIKE ''V35%''
                 AND rowid BETWEEN :start_id AND :end_id';

  -- run the task
  DBMS_PARALLEL_EXECUTE.run_task(task_name      => 'update_accounts_task',
                                 sql_stmt       => v_sql,
                                 language_flag  => DBMS_SQL.NATIVE,
                                 parallel_level => 10);
END;

The user creating the task must be granted the CREATE JOB privilege.

Based on article by Tim Hall accessible here: DBMS_PARALLEL_EXECUTE at Oracle Base