Re: Checkpoint_segments optimal value

John R Pierce <pierce@xxxxxxxxxxxx> · Thu, 17 Jul 2014 16:51:33 -0700



    On 7/17/2014 11:28 AM, Prabhjot Sheena
      wrote:

    
      SELECT account.id,
      account.organization_id, run.application_id, work_unit.script, work_unit.id,
      work_unit.start_time, run.id, work_unit.priority  FROM
      work_unit, run, account  WHERE  work_unit.status = 3 AND
      work_unit.run_id = run.id
      AND work_unit.type != 1 AND run.status = 1 AND run.account_id = account.id
    

    that query is an implied 3-way join.  it would be clearer to write
    it like...

    
    SELECT account.id,
    account.organization_id, run.application_id, work_unit.script, work_unit.id,
    work_unit.start_time, run.id, work_unit.priority  

        FROM work_unit 

            JOIN run ON work_unit.run_id = run.id 

            JOIN account  ON run.account_id = account.id
    

        WHERE work_unit.status = 3 AND work_unit.type != 1 AND
    run.status = 1;

    
    postgres would (or at least should) treat this exactly the same, but
    its clearer what the query is doing when its written this way.

    
    -- 
john r pierce                                      37N 122W
somewhere on the middle of the left coast