Oracle-L: parallel index creation again:in which case, can we use parallel with single cpu env?

From: chao_ping <chao_ping_at_vip.163.com>
Date: Wed, 12 Feb 2003 06:49:10 -0800
Message-ID: <F001.0054A983.20030212064910@fatcity.com>

hi, dba friends:

	some paper said, pqo should only be used in SMP machines, while  others say, We can also use pqo in uniprocessor machines in some case.
	I am trying to use parallel index creation in the following env:

Dell 1650 with 3 scsi160 disks and 1 CPU and 2G memory. Oracle 9.2
Table contains 22000000 records,1.2GB
Table tablespace contains 3 datafiles , 400M, 400M and 600M, on seperate 3 disks. Index tablespace contains 3 datafiles, 200M, 200M and 200M on seperate 3 disks.

SQL> set term on timing on echo on feedback on SQL> alter session set sort_area_size = 100000000; Session altered.
Elapsed: 00:00:00.01
SQL> create index idx_serial on viewcount( SID_LIST) nologging parallel (degree 2) tablespace pqind; Index created.
Elapsed: 00:18:01.36
SQL> drop index idx_serial;
Elapsed: 00:00:00.16
SQL> create index idx_serial on viewcount( SID_LIST) nologging tablespace pqind; Elapsed: 00:06:48.04

	This machine is exclusived used my me and It seems that PQO is rather slower than single thread. So is it still possible to use PQO on single processor machines?
	Please share your experience and idear.
	Thanks.

Wait event like:

Top 5 Timed Events

~~~~~~~~~~~~~~~~~~                                                     % Total
Event                                               Waits    Time (s) Ela Time
-------------------------------------------- ------------ ----------- --------
PX qref latch                                      48,371         415    40.94
PX Deq: Execute Reply                                 176         340    33.54
PX Deq Credit: send blkd                           47,704         248    24.47
control file parallel write                           112           5      .48
PX Deq Credit: need buffer                          1,835           4      .38
          -------------------------------------------------------------

^LWait Events for DB: ORA9 Instance: ora9 Snaps: 19 -20
-> s - second
-> cs - centisecond - 100th of a second
-> ms - millisecond - 1000th of a second

Regards
zhu chao
msn:chao_ping_at_163.com
www.happyit.net
www.cnoug.org(China Oracle User Group)

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Received on Wed Feb 12 2003 - 08:49:10 CST