Run/execute multiple procedures in Parallel - Orac

问题:

I have an Activity table which is getting all the table events of the system. Events like new orders, insertion/deletion on all the system tables will be inserted into this table. So, the no of events/sec is really huge for Activity table.

Now, I want to process the incoming events based on the business logic depending on the table responsible for raising the event. Every table may have different procedure to do the processing.

I used the same link Parallelizing calls in PL/SQL

As a solution I have created multiple dbms_scheduler jobs which will be called at the same time. All these jobs (JOB1, JOB2--- - -JOB10) will have the same procedure (ProcForAll_Processing) as JOB_ACTION to achieve parallel processing.

begin
    dbms_scheduler.run_job('JOB1',false);
    dbms_scheduler.run_job('JOB2',false);
  end; 

ProcForAll_Processing: This procedure in turn will call 6 other procedures Proc1,proc2,proc3 --- -- - -- - Proc6 in sequential manner. I want to achieve parallel processing for these as well.

P.S: We can’t create further jobs to achieve parallel processing in ProcForAll_Processing proc as it may lead to consume further resources and also DBA is not agreeing for creating further jobs. Also, I can't use dbms_parallel_execute for parallel processing.

Please help me as I am really stuck to get it done

回答1:

It is impossible in general case without jobs, and it will make multiple sessions for this. There is no such thing as multithreading PL\SQL with a few exceptions. One of them is parallel execution of sql statements [1]. So there are some attempts to abuse this stuff for parallel execution of PL\SQL code, for example try to look here [2].

But as i've said it's abuse IMHO.

Reference:

1. https://docs.oracle.com/cd/B19306_01/server.102/b14223/usingpe.htm
2. http://www.williamrobertson.net/documents/parallel-plsql-launcher.html

回答2:

Get a new DBA. Or even better, cut them out of any decision making processes. A DBA should not review your code and should not tell you to not create jobs, unless there is a good, specific reason.

Using DBMS_SCHEDULER to run things in parallel is by far the easiest and most common way to achieve this result. Of course it's going to consume more resources, that's what parallelism will inevitably do.

Another, poorer option, is to use parallel pipelined table functions. It's an advanced PL/SQL feature that can't be easily explained in a simple example. The best I can do is refer you to the manual.

回答3:

You should try to use DBMS_PARALLEL_EXECUTE (since RDBMS 11).
https://blogs.oracle.com/warehousebuilder/entry/parallel_processing_in_plsql
https://oracle-base.com/articles/11g/dbms_parallel_execute_11gR2