statspack rac comment is needed

From: hopehope_123 <hopehope_123_at_yahoo.com>
Date: 25 Aug 2005 00:05:42 -0700
Message-ID: <1124953542.954469.131770@z14g2000cwz.googlegroups.com>

Hi ,

The below output belongs to the my datawarehouse system that is redhat linux 2.1 advanced server , 4 ia64 cpus , 8gb.ram , 1hba (fiber) , emc raid 10 , 2 nodes , ocfs.

First of all, is it possible that statspack can have a bug when the duration is long. Here this output reflects the 1,021.38 seconds and during this time our etl process which does very heavy parallel insert , update , merge jobs , but the logical reads and phy.reads values are very low.

On the other hand , the main wait events are all rac related.

PX Deq Credit: send blkd                        1,831,252     389,689
 68.05
db file sequential read                        10,652,126      83,586

14.60

389689 / 1831252 = 0.212 or 212 msec. average ! I have gigabit interconnect!

83586 / 10652126 = 0.007 msec or 7msec per read on average.

It seems the disk is faster than the gigabit. ( I use ocfs which uses direct io , i cant monitor the emc part so dont know whether this io really occurs on emc or is supplied by using the emc disk cache)

Any comments will be appreciated.

Begin Snap:     213 24-Aug-05 16:21:51   34,386       1.8
  End Snap:     214 25-Aug-05 09:23:14   73,509       1.5
   Elapsed:            1,021.38 (mins)

Cache Sizes (end)

               Buffer Cache:       512M      Std Block Size:        16K
           Shared Pool Size:       656M          Log Buffer:     2,048K

Load Profile
~~~~~~~~~~~~                            Per Second       Per
Transaction
                                   ---------------
---------------
                  Redo size:             50,788.47
3,081,653.16
              Logical reads:              6,153.35
373,362.39
              Block changes:                658.04
39,927.61
             Physical reads:                360.22
21,856.77
            Physical writes:                 57.06
3,462.15
                 User calls:                 34.00
2,063.14
                     Parses:                  1.84
111.68
                Hard parses:                  0.06
3.66
                      Sorts:                  0.30
18.11
                     Logons:                 10.24

621.49

Top 5 Timed Events

% Total

Event                                               Waits    Time (s)

Ela Time

-------------------------------------------- ------------ -----------
--------
PX Deq Credit: send blkd                        1,831,252     389,689
 68.05
db file sequential read                        10,652,126      83,586
 14.60
PX Deq: Signal ACK                                506,287      59,842
 10.45
CPU time                                                       12,132
  2.12
IPC send completion sync                        3,549,637       9,433
  1.65
          -------------------------------------------------------------

Received on Thu Aug 25 2005 - 02:05:42 CDT