Run Parallel

Question

Hi,
we have a database package which dynamically execute index rebuild/analyze table commands using EXECUTE IMMEDIATE statement.
The execute immediate statement is within a for loop.
We would like to know whether we can run these statements Parallel, rather executing them sequentially with-in for loop.
Sample
FOR r_ind_rebuild IN c_ind_rebuild (r_tabs.PARAMETER_VALUE)
LOOP
EXECUTE IMMEDIATE r_ind_rebuild.text;
END LOOP;

Answer 1

I think you should parallelize your rebuild Unless you hit an unexpected oracle event like buffer busy... this way you will fully utilize the your disk system.
I have 3 methods for that
1 - you can use dbms_job to submit your index rebuilds as jobs and run them in parallel.
I found the following code on internet. You can use DBMS_JOB.ISUBMIT to give them specific job ID then after they finish you can delete these jobs.
reference
http://www.ulaska.com/oracle/oracle_procedure_job_submit.html
CREATE OR REPLACE PROCEDURE DBMS_JOB_SUBMIT(PROC_NAME IN VARCHAR2)
IS
     INT_JOB_ID NUMBER := NULL;
BEGIN
     DBMS_JOB.SUBMIT (
         job => INT_JOB_ID,
          what => PROC_NAME || ';', -- What to run
          next_date => SYSDATE, -- Start right away
          interval => NULL -- Run only once
     COMMIT;
END;2 - you can have a definition table which contains the rebuild index definitions. It will have a status column (RUNNING, NOT STARTED, FINISHED)
they you can call more than one session (from jobs or bash scripts ) to get the next job whose status is NOT STARTED then chage status to RUNNING and after all change it to FINISHED. This way each job rebuilds mutually exclusive indexes.
3 - use oracle way of parallelism.
-get the parallelism defined on the index i.e PP=5
alter index YYYYY rebuild  parallel 5 ;
-if the index is not defined as paralel at the begining then set it to noparallel
alter index YYYYY noparallel ;