Apress.Expert.Oracle.Database.Architecture.9i.and.10g.Programming.Techniques.and.Solutions.Sep.2005

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CHAPTER 14 ■ PARALLEL EXECUTION
big_table-ORA10G> create table t2
2 as
3 select object_id id, object_name text, 0 session_id
4 from big_table
5 where 1=0;
Table created.
We are going to use the job queues built into the database to parallel process our procedure.
We will schedule some number of jobs. Each job is our procedure slightly modified to
just process the rows in a given rowid range.
■Note In Oracle 10g, you could use the scheduler for something this simple, but in order to make the
example 9i compatible, we’ll use the job queues here.
To efficiently support the job queues, we’ll use a parameter table to pass inputs to our jobs:
big_table-ORA10G> create table job_parms
2 ( job number primary key,
3 lo_rid rowid,
4 hi_rid rowid
5 )
6 /
Table created.
This will allow us to just pass the job ID into our procedure, so it can query this table to
get the rowid range it is to process. Now for our procedure. The code in bold is the new code
we’ll be adding:
big_table-ORA10G> create or replace
2 procedure serial( p_job in number )
3 is
4 l_rec job_parms%rowtype;
5 begin
6 select * into l_rec
7 from job_parms
8 where job = p_job;
9
10 for x in ( select object_id id, object_name text
11 from big_table
12 where rowid between l_rec.lo_rid
13 and l_rec.hi_rid )
14 loop
15 -- complex process here
16 insert into t2 (id, text, session_id )
17 values ( x.id, x.text, p_job );
18 end loop;