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

CHAPTER 14 ■ PARALLEL EXECUTION 645
19
20 delete from job_parms where job = p_job;
21 commit;
22 end;
23 /
Procedure created.
As you can see, it is not a significant change. Most of the added code was simply to get our
inputs and the rowid range to process. The only change to our logic was the addition of the
predicate on lines 12 and 13.
Now let’s schedule our job. We’ll use a rather complex query using analytics to divide the
table. The innermost query on lines 19 through 26 breaks the data into eight groups in this
case. The first sum on line 22 is computing a running total of the sum of blocks; the second
sum on line 23 is the total number of blocks. If we integer divide the running total by the desired
“chunk size” (the total size divided by 8 in this case), we can create groups of files/blocks that
cover about the same amount of data. The query on lines 8 through 28 finds the high and low
file numbers and block numbers by GRP, and returns the distinct entries. It builds the inputs
we can then send to DBMS_ROWID to create the rowids Oracle wants. We take that output and,
using DBMS_JOB, submit a job to process the rowid range:
big_table-ORA10G> declare
2 l_job number;
3 begin
4 for x in (
5 select dbms_rowid.rowid_create
( 1, data_object_id, lo_fno, lo_block, 0 ) min_rid,
6 dbms_rowid.rowid_create
( 1, data_object_id, hi_fno, hi_block, 10000 ) max_rid
7 from (
8 select distinct grp,
9 first_value(relative_fno)
over (partition by grp order by relative_fno, block_id
10 rows between unbounded preceding and unbounded following) lo_fno,
11 first_value(block_id )
over (partition by grp order by relative_fno, block_id
12 rows between unbounded preceding and unbounded following) lo_block,
13 last_value(relative_fno)
over (partition by grp order by relative_fno, block_id
14 rows between unbounded preceding and unbounded following) hi_fno,
15 last_value(block_id+blocks-1)
over (partition by grp order by relative_fno, block_id
16 rows between unbounded preceding and unbounded following) hi_block,
17 sum(blocks) over (partition by grp) sum_blocks
18 from (
19 select relative_fno,
20 block_id,
21 blocks,
22 trunc( (sum(blocks) over (order by relative_fno, block_id)-0.01) /