Re: 9.2 - Parallel Query Not Working

On Thu, Mar 27, 2008 at 1:51 PM, Tony Adolph <tony.adolph.dba_at_gmail.com> wrote:

> You'll only get parallel table access for full table scans, .i.e. the
> table is not accessed via index lookup.
>
>

If you are saying that only FTS run in parallel, and not index access, that is not a correct statement. Index access can be parallelized.

Here is a execution plan where the table is accessed via index lookup (rowids gotten from the index scan). Both the index and table access are parallel.

SELECT * FROM FACT_TABLE
WHERE KEY_FACT_ID>=69329730003700001 AND       KEY_FACT_ID"<=69329730003700010

| Id  | Operation                            | Name        |    TQ  |IN-OUT|

|   0 | SELECT STATEMENT                     |             |        |
|            |
|   1 |  PX COORDINATOR                      |             |        |
|            |
|   2 |   PX SEND QC (RANDOM)                | :TQ10000    |  Q1,00 | P->S |
QC (RAND)  |
|   3 |    PX PARTITION HASH ALL             |             |  Q1,00 | PCWC
|            |
|   4 |     TABLE ACCESS BY LOCAL INDEX ROWID| FACT_TABLE  |  Q1,00 | PCWP
|            |
|   5 |      INDEX RANGE SCAN                | FACT_PK     |  Q1,00 | PCWP
|            |
-----------------------------------------------------------------------------------------

 Predicate Information (identified by operation id):

  5 - access("KEY_FACT_ID">=69329730003700001 AND

             "KEY_FACT_ID"<=69329730003700010)

-- 
Regards,

Greg Rahn
http://structureddata.org

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