RE: [External] Wierd Parallel DDL Behaviour ?
- From: Gokul Gopal <gokulkumar.gopal@xxxxxxxxx>
- To: "Chitale, Hemant K" <Hemant-K.Chitale@xxxxxx>, Oracle-L Group <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 16 Dec 2016 08:18:51 +0530
Thanks Hemant.
Interestingly, if I remove /*+ parallel(4) */ and replace it with "parallel 4"
at the statement level, it stops working. Any idea why this might be happening?
Gokul Gopal
-----Original Message-----
From: "Chitale, Hemant K" <Hemant-K.Chitale@xxxxxx>
Sent: 16/12/2016 07:09
To: "gokulkumar.gopal@xxxxxxxxx" <gokulkumar.gopal@xxxxxxxxx>; "Oracle-L Group"
<oracle-l@xxxxxxxxxxxxx>
Subject: RE: [External] Wierd Parallel DDL Behaviour ?
create /*+ parallel(4) */ table t15
Since at least 7.3.4
See the CREATE TABLE statement and the PARALLEL Clause in the 7.3.4
documentation available online
http://docs.oracle.com/pdf/A32538_1.pdf
(back then, Parallel Query was a licensed Option in the database)
Hemant K Chitale
From: oracle-l-bounce@xxxxxxxxxxxxx [
mailto:oracle-l-bounce@xxxxxxxxxxxxx] On ;
Behalf Of Gokul Kumar Gopal
Sent: Friday, December 16, 2016 4:07 AM
To: Oracle-L Group
Subject: [External] Wierd Parallel DDL Behaviour ?
Hello,
I am trying to understand the following run..
sqlplus <user>/<pwd>@db
SQL*Plus: Release 11.2.0.1.0 Production on Fri Dec 16 01:25:38 2016
Copyright (c) 1982, 2010, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management,
OLAP,
Data Mining and Real Application Testing options
SQL> select * from v$mystat where rownum <= 1;
SID STATISTIC# VALUE
---------- ---------- ----------
278 0 0
SQL>
SQL>
SQL> alter session force parallel DDL;
Session altered.
SQL> alter session force parallel DML;
Session altered.
SQL> alter session force parallel query;
Session altered.
SQL>
SQL> create table t15 as select * from dba_objects union all select * from
dba_objects;
^C
At this point, I had to stop the process as it created 289 sessions and was
still running..
I made some changes and re-ran..
sqlplus <user>/<pwd>@db
SQL*Plus: Release 11.2.0.1.0 Production on Fri Dec 16 01:29:34 2016
Copyright (c) 1982, 2010, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management,
OLAP,
Data Mining and Real Application Testing options
SQL> alter session force parallel DDL;
Session altered.
SQL> alter session force parallel DML;
Session altered.
SQL> alter session force parallel query;
Session altered.
SQL>
SQL> set timing on
SQL>
SQL> select * from v$mystat where rownum <= 1;
SID STATISTIC# VALUE
---------- ---------- ----------
278 0 0
Elapsed: 00:00:00.50
SQL>
SQL> create /*+ parallel(4) */ table t15 as select * from dba_objects union all
select * from dba_objects;
Table created.
Elapsed: 00:00:08.02
The highlighted part is the only changed I made, but I cannot explain why this
worked with no additional sessions.. I have never seen this syntax mentioned
anywhere but a casual try worked.
Does anyone know how this works ?
Rgds,
Gokul
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