Jonathan
Imagine a query which has many selects in the main select plus say subqueries
yielding several query blocks ,and we only need to run parallelism for 1 or 2
query blocks not the whole main sql, yet we can not edit the sql to add hints
and of course can not alter session (which will make the whole thing parallel
of course).
how can we use a specific query block name via (sql profile or sql patch) to
make it parallel ?
On Jan 17, 2021, at 5:52 AM, Jonathan Lewis <jlewisoracle@xxxxxxxxx> wrote:
PARALLEL() is a statement level or object level hint, not a query block hint.
We can't see your query or the definitions of any tables of views used in your
query so we can't tell you why you're seeing so many Unused parallel hints, or
why 8 is the degree of parallelism reported. I haven't seen any notes anywhere
explaining why the parallel() hint never seems to get into the Outline
Information, but possibly it's a deliberate choice aimed at encouraging people
to enable automatic parallelism.
If you want to create a baseline, patch, or profile with a "parallel" hint in
it you'll probably have to use SHARED(...) rather than PARALLEL(...)
Regards
Jonathan Lewis
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On Sat, 16 Jan 2021 at 18:09, Moustafa Ahmed
<moustafa_dba@xxxxxxxxxxx<mailto:moustafa_dba@xxxxxxxxxxx>> wrote:
Hello folks
Running dbms_xplan.display_cursor with advanced options on a sql running with
parallel slaves I can see as you know “Outline Data” and QBnames..
1-I know the sql is running in parallel.
2-I see “PQ_DISTRIBUTE_WINDOW”, “PQ_DISTRIBUTE” in outline data.
3-no related parallel variables in “OPT_PARAM”.
4-hint report part shows
Hint Report (identified by operation id / Query Block Name / Object Alias):
Total hints for statement: 6 (U - Unused (5))
---------------------------------------------------------------------------
0 - STATEMENT
U - PARALLEL(8) / duplicate hint
U - PARALLEL(8) / duplicate hint
U - PARALLEL(8) / duplicate hint
U - PARALLEL(8) / hint overridden by another in parent query block
U - PARALLEL(8) / hint overridden by another in parent query block
- PARALLEL(8)
1-Why I can not see a “Query Block” with the parralele hint and its degree?
2-what should I do If want to inject the same parralel hint with same degree on
same qb?
