Update in table partition by hash

Question

I have a table partitioned by hash. I want to make some updates (not on the partition key column and also not based on this column, i.e this column is not used in where clause).
Do I need to specify partition name in the query?
For a concrete example:
CREATE TABLE invoices
(invoice_id NUMBER NOT NULL,
customer_id NUMBER NOT NULL,
invoice_date DATE NOT NULL,
comments VARCHAR2(500))
PARTITION BY HASH (customer_id)
PARTITIONS 10
primary key is customer_id + invoice_date
I need to update invoice_id based on the rowid, like update invoices set invoice_id = MEMO_ID_1SQ.nextval where rowid = <variable>. I will be running this query from multiple processes and I want to make sure they are hitting different partitions, so they actually run in parallel.
Thanks in advance,
Radu

Answer 1

Radu,
You can use parallel hint on your update statement.
update /*+ PARALLEL(invoices, 4) */  invoices set invoice_id = MEMO_ID_1SQ.nextval where rowid = <variable>;See following execution plan for both with and without using parallel option
SQL> update interfacerecords set status=1 where interfaceid=5;
200000 rows updated.
Elapsed: 00:00:03.75
Execution Plan
Plan hash value: 3154550297
| Id  | Operation          | Name             | Rows  | Bytes | Cost (%CPU)| Time     |
|   0 | UPDATE STATEMENT   |                  |   200K|  3125K|   128   (3)| 00:00:02 |
|   1 |  UPDATE            | INTERFACERECORDS |       |       |            |          |
|*  2 |   TABLE ACCESS FULL| INTERFACERECORDS |   200K|  3125K|   128   (3)| 00:00:02 |
Predicate Information (identified by operation id):
   2 - filter("INTERFACEID"=5)
Statistics
        262  recursive calls
     458353  db block gets
       1539  consistent gets
        378  physical reads
   91750476  redo size
        655  bytes sent via SQL*Net to client
        585  bytes received via SQL*Net from client
          3  SQL*Net roundtrips to/from client
          1  sorts (memory)
          0  sorts (disk)
     200000  rows processed
SQL> commit;
Commit complete.
Elapsed: 00:00:00.00
SQL> set autotrace traceonly;
SQL> set timi on;
SQL> set lines 400;
SQL> update /*+ PARALLEL(interfacerecords, 4) */ interfacerecords set status=5 where status=1;
200000 rows updated.
Elapsed: 00:00:02.48
Execution Plan
Plan hash value: 2940696107
| Id  | Operation             | Name             | Rows  | Bytes | Cost (%CPU)| Time     |    TQ  |IN-OUT| PQ Distrib |
|   0 | UPDATE STATEMENT      |                  |     1 |    13 |    35   (0)| 00:00:01 |        |   |       |
|   1 |  UPDATE               | INTERFACERECORDS |       |       |            |          |        |   |       |
|   2 |   PX COORDINATOR      |                  |       |       |            |          |        |   |       |
|   3 |    PX SEND QC (RANDOM)| :TQ10000         |     1 |    13 |    35   (0)| 00:00:01 |  Q1,00 | P->S | QC (RAND)  |
|   4 |     PX BLOCK ITERATOR |                  |     1 |    13 |    35   (0)| 00:00:01 |  Q1,00 | PCWC |            |
|*  5 |      TABLE ACCESS FULL| INTERFACERECORDS |     1 |    13 |    35   (0)| 00:00:01 |  Q1,00 | PCWP |            |
Predicate Information (identified by operation id):
   5 - filter("STATUS"=1)
Statistics
        309  recursive calls
     214609  db block gets
      30287  consistent gets
          0  physical reads
   63356488  redo size
        654  bytes sent via SQL*Net to client
        617  bytes received via SQL*Net from client
          3  SQL*Net roundtrips to/from client
          3  sorts (memory)
          0  sorts (disk)
     200000  rows processedRegards