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Need help to analysis "foreground and background wait events" on statspack report for oracle databas

User_6KE3DApr 28 2015 — edited May 4 2015

Hi: I'm analyzing this STATSPACK report: it is "volume test" on our UAT server, so most input is from 'bind variables'.  Our shared pool is well utilized in oracle.  Oracle redo logs is not appropriately configured on this server, as in 'Top 5 wait events' there are 2 for redos.

I need to know what else information can be dig-out from 'foreground wait events' & 'background wait events', and what can assist us to better understanding, in combination of 'Top 5 wait event's, that how the server/test went?  it could be overwelming No. of wait events, so appreciate any helpful diagnostic or analysis.  Database is oracle 11.2.0.4 upgraded from 11.2.0.3, on IBM AIX power system 64bit, level 6.x


STATSPACK report for


Database    DB Id    Instance     Inst Num  Startup Time   Release     RAC


~~~~~~~~ ----------- ------------ -------- --------------- ----------- ---

700000XXX   XXX              1 22-Apr-15 12:12 11.2.0.4.0  NO


Host Name             Platform                CPUs Cores Sockets   Memory (G)

~~~~ ---------------- ---------------------- ----- ----- ------- ------------

     dXXXX_XXX    AIX-Based Systems (64-     2     1       0         16.0


Snapshot       Snap Id     Snap Time      Sessions Curs/Sess Comment

~~~~~~~~    ---------- ------------------ -------- --------- ------------------

Begin Snap:       5635 22-Apr-15 13:00:02      114       4.6

  End Snap:       5636 22-Apr-15 14:00:01      128       8.8

   Elapsed:      59.98 (mins) Av Act Sess:       0.6

   DB time:      35.98 (mins)      DB CPU:      19.43 (mins)


Cache Sizes            Begin        End

~~~~~~~~~~~       ---------- ----------

    Buffer Cache:     2,064M              Std Block Size:         8K

     Shared Pool:     3,072M                  Log Buffer:    13,632K

Load Profile              Per Second    Per Transaction    Per Exec    Per Call

~~~~~~~~~~~~      ------------------  ----------------- ----------- -----------

      DB time(s):                0.6                0.0        0.00        0.00

       DB CPU(s):                0.3                0.0        0.00        0.00

       Redo size:          458,720.6            8,755.7

   Logical reads:           12,874.2              245.7

   Block changes:            1,356.4               25.9

  Physical reads:                6.6                0.1

Physical writes:               61.8                1.2

      User calls:            2,033.7               38.8

          Parses:              286.5                5.5

     Hard parses:                0.5                0.0

W/A MB processed:                1.7                0.0

          Logons:                1.2                0.0

        Executes:              801.1               15.3

       Rollbacks:                6.1                0.1

    Transactions:               52.4


Instance Efficiency Indicators

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

            Buffer Nowait %:  100.00       Redo NoWait %:  100.00

            Buffer  Hit   %:   99.98  Optimal W/A Exec %:  100.00

            Library Hit   %:   99.77        Soft Parse %:   99.82

         Execute to Parse %:   64.24         Latch Hit %:   99.98

Parse CPU to Parse Elapsd %:   53.15     % Non-Parse CPU:   98.03


Shared Pool Statistics        Begin   End

                               ------  ------

             Memory Usage %:   10.50   12.79

    % SQL with executions>1:   69.98   78.37

  % Memory for SQL w/exec>1:   70.22   81.96

Top 5 Timed Events                                                    Avg %Total

~~~~~~~~~~~~~~~~~~                                                   wait   Call

Event                                            Waits    Time (s)   (ms)   Time

----------------------------------------- ------------ ----------- ------ ------

CPU time                                                       847          50.2

enq: TX - row lock contention                    4,480         434     97   25.8

log file sync                                  284,169         185      1   11.0

log file parallel write                        299,537         164      1    9.7

log file sequential read                           698          16     24    1.0

Host CPU  (CPUs: 2  Cores: 1  Sockets: 0)

~~~~~~~~              Load Average

                      Begin     End      User  System    Idle     WIO     WCPU

                    ------- -------   ------- ------- ------- ------- --------

                       1.16    1.84     19.28   14.51   66.21    1.20   82.01


Instance CPU

~~~~~~~~~~~~                                       % Time (seconds)

                                            -------- --------------

                     Host: Total time (s):                  7,193.8

                  Host: Busy CPU time (s):                  2,430.7

                   % of time Host is Busy:      33.8

             Instance: Total CPU time (s):                  1,203.1

          % of Busy CPU used for Instance:      49.5

        Instance: Total Database time (s):                  2,426.4

  %DB time waiting for CPU (Resource Mgr):       0.0


Memory Statistics                       Begin          End

~~~~~~~~~~~~~~~~~                ------------ ------------

                  Host Mem (MB):     16,384.0     16,384.0

                   SGA use (MB):      7,136.0      7,136.0

                   PGA use (MB):        282.5        361.4

    % Host Mem used for SGA+PGA:         45.3         45.8

Foreground Wait Events  DB/Inst: XXXXXs  Snaps: 5635-5636

-> Only events with Total Wait Time (s) >= .001 are shown

-> ordered by Total Wait Time desc, Waits desc (idle events last)


                                                             Avg          %Total

                                          %Tim Total Wait   wait    Waits   Call

Event                               Waits  out   Time (s)   (ms)     /txn   Time

---------------------------- ------------ ---- ---------- ------ -------- ------

enq: TX - row lock contentio        4,480    0        434     97      0.0   25.8

log file sync                     284,167    0        185      1      1.5   11.0

Disk file operations I/O            8,741    0          4      0      0.0     .2

direct path write                  13,247    0          3      0      0.1     .2

db file sequential read             6,058    0          1      0      0.0     .1

buffer busy waits                   1,800    0          1      1      0.0     .1

SQL*Net more data to client        29,161    0          1      0      0.2     .1

direct path read                    7,696    0          1      0      0.0     .0

db file scattered read                316    0          1      2      0.0     .0

latch: shared pool                    144    0          0      2      0.0     .0

CSS initialization                     30    0          0      3      0.0     .0

cursor: pin S                          10    0          0      9      0.0     .0

row cache lock                         41    0          0      2      0.0     .0

latch: row cache objects               19    0          0      3      0.0     .0

log file switch (private str            8    0          0      7      0.0     .0

library cache: mutex X                 28    0          0      2      0.0     .0

latch: cache buffers chains            54    0          0      1      0.0     .0

latch free                            290    0          0      0      0.0     .0

control file sequential read        1,568    0          0      0      0.0     .0

log file switch (checkpoint             4    0          0      6      0.0     .0

direct path sync                        8    0          0      3      0.0     .0

latch: redo allocation                 60    0          0      0      0.0     .0

SQL*Net break/reset to clien           34    0          0      1      0.0     .0

latch: enqueue hash chains             45    0          0      0      0.0     .0

latch: cache buffers lru cha            7    0          0      2      0.0     .0

latch: session allocation               5    0          0      1      0.0     .0

latch: object queue header o            6    0          0      1      0.0     .0

ASM file metadata operation            30    0          0      0      0.0     .0

latch: In memory undo latch            15    0          0      0      0.0     .0

latch: undo global data                 8    0          0      0      0.0     .0

SQL*Net message from client     6,362,536    0    278,225     44     33.7

jobq slave wait                     7,270  100      3,635    500      0.0

SQL*Net more data from clien        7,976    0         15      2      0.0

SQL*Net message to client       6,362,544    0          8      0     33.7

-------------------------------------------------------------

Background Wait Events  DB/Inst: XXXXXs  Snaps: 5635-5636

-> Only events with Total Wait Time (s) >= .001 are shown

-> ordered by Total Wait Time desc, Waits desc (idle events last)

                                                             Avg          %Total

                                          %Tim Total Wait   wait    Waits   Call

Event                               Waits  out   Time (s)   (ms)     /txn   Time

---------------------------- ------------ ---- ---------- ------ -------- ------

log file parallel write           299,537    0        164      1      1.6    9.7

log file sequential read              698    0         16     24      0.0    1.0

db file parallel write              9,556    0         13      1      0.1     .8

os thread startup                     146    0         10     70      0.0     .6

control file parallel write         2,037    0          2      1      0.0     .1

Log archive I/O                        35    0          1     30      0.0     .1

LGWR wait for redo copy             2,447    0          0      0      0.0     .0

db file async I/O submit            9,556    0          0      0      0.1     .0

db file sequential read               145    0          0      2      0.0     .0

Disk file operations I/O              349    0          0      0      0.0     .0

db file scattered read                 30    0          0      4      0.0     .0

control file sequential read        5,837    0          0      0      0.0     .0

ADR block file read                    19    0          0      4      0.0     .0

ADR block file write                    5    0          0     15      0.0     .0

direct path write                      14    0          0      2      0.0     .0

direct path read                        3    0          0      7      0.0     .0

latch: shared pool                      3    0          0      6      0.0     .0

log file single write                  56    0          0      0      0.0     .0

latch: redo allocation                 53    0          0      0      0.0     .0

latch: active service list              1    0          0      3      0.0     .0

latch free                             11    0          0      0      0.0     .0

rdbms ipc message                 314,523    5     57,189    182      1.7

Space Manager: slave idle wa        4,086   88     18,996   4649      0.0

DIAG idle wait                      7,185  100      7,186   1000      0.0

Streams AQ: waiting for time            2   50      4,909 ######      0.0

Streams AQ: qmn slave idle w          129    0      3,612  28002      0.0

Streams AQ: qmn coordinator           258   50      3,612  14001      0.0

smon timer                             43    2      3,605  83839      0.0

pmon timer                          1,199   99      3,596   2999      0.0

SQL*Net message from client        17,019    0         31      2      0.1

SQL*Net message to client          12,762    0          0      0      0.1

class slave wait                       28    0          0      0      0.0

thank you very much!

This post has been answered by Franck Pachot on Apr 30 2015
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