DB FILE PARALLEL WRITE

The db file parallel write wait event in last 24 hours.

 $ sqlplus /nolog

SQL*Plus: Release 10.2.0.1.0 - Production on Wed Feb 1 13:00:42 2012

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

SQL> conn /as sysdba

Connected.

SQL> show SGA

Total System Global Area 1577058304 bytes

Fixed Size                  1978944 bytes

Variable Size             268438976 bytes

Database Buffers         1291845632 bytes

Redo Buffers               14794752 bytes

WORKLOAD REPOSITORY report for

DB Name         DB Id    Instance     Inst Num Release     RAC Host
------------ ----------- ------------ -------- ----------- --- ------------
TRSPRD        1780995754 TRSPRD              1 10.2.0.1.0  NO  ctmtrs

              Snap Id      Snap Time      Sessions Curs/Sess
            --------- ------------------- -------- ---------
Begin Snap:     30378 24-Feb-11 09:00:46        36       7.9
  End Snap:     30402 25-Feb-11 09:01:06        34       7.6
   Elapsed:            1,440.33 (mins)
   DB Time:           17,493.07 (mins)

Top 5 Timed Events                                         Avg %Total
~~~~~~~~~~~~~~~~~~                                        wait   Call
Event                                 Waits    Time (s)   (ms)   Time Wait Class
------------------------------ ------------ ----------- ------ ------ ----------
db file sequential read          27,411,103     881,855     32   84.0   User I/O
db file parallel write            1,691,014      63,778     38    6.1 System I/O
CPU time                                         50,099           4.8
free buffer waits                 2,540,169      44,494     18    4.2 Configurat
db file scattered read            5,852,398      29,023      5    2.8   User I/O

Please compare the AWR report  on 5th Feb 2011

 $ vi awrrpt_1_29913_29936.txt
"awrrpt_1_29913_29936.txt" 2949 lines, 188755 characters

 WORKLOAD REPOSITORY report for

 DB Name         DB Id    Instance     Inst Num Release     RAC Host
------------ ----------- ------------ -------- ----------- --- ------------
TRSPRD        1780995754 TRSPRD              1 10.2.0.1.0  NO  ctmtrs

               Snap Id      Snap Time      Sessions Curs/Sess
            --------- ------------------- -------- ---------
Begin Snap:     29913 05-Feb-11 00:00:47        27      15.7
  End Snap:     29936 05-Feb-11 23:00:45        29      11.6
   Elapsed:            1,379.97 (mins)
   DB Time:            1,978.37 (mins)

Top 5 Timed Events                                         Avg %Total
~~~~~~~~~~~~~~~~~~                                        wait   Call
Event                                 Waits    Time (s)   (ms)   Time Wait Clas
s
------------------------------ ------------ ----------- ------ ------ ----------
db file sequential read           9,006,930      79,648      9   67.1   User I/O
Backup: sbtwrite2                 3,060,106      51,124     17   43.1 Administra
CPU time                                         25,331          21.3
db file parallel write            1,687,418       4,605      3    3.9 System I/O
log file parallel write             133,726       3,523     26    3.0 System I/O

$ vi awrrpt_1_30360_30384.txt
"awrrpt_1_30360_30384.txt" 3191 lines, 205058 characters

WORKLOAD REPOSITORY report for

DB Name         DB Id    Instance     Inst Num Release     RAC Host
------------ ----------- ------------ -------- ----------- --- ------------
TRSPRD        1780995754 TRSPRD              1 10.2.0.1.0  NO  ctmtrs

              Snap Id      Snap Time      Sessions Curs/Sess
            --------- ------------------- -------- ---------
Begin Snap:     30360 23-Feb-11 15:00:28        39       7.5
  End Snap:     30384 24-Feb-11 15:00:10        44       9.6
   Elapsed:            1,439.71 (mins)
   DB Time:           18,730.04 (mins)

Please help to investigate the db file parallel write wait event from the SAN perspective.

 Top 5 Timed Events                                         Avg %Total
~~~~~~~~~~~~~~~~~~                                        wait   Call
Event                                 Waits    Time (s)   (ms)   Time Wait Class
------------------------------ ------------ ----------- ------ ------ ----------
db file sequential read          25,427,418   1,022,499     40   91.0   User I/O
db file parallel write            2,033,366      68,454     34    6.1 System I/O
CPU time                                         38,243           3.4
free buffer waits                 1,029,494      15,750     15    1.4 Configurat
db file scattered read            3,413,106      15,376      5    1.4   User I/O
          -------------------------------------------------------------

http://blog.csdn.net/tianlesoftware/article/details/6545064

http://sharklove.itpub.net/post/660/279769