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library cache pin wait

From: VIVEK_SHARMA <VIVEK_SHARMA_at_infosys.com>
Date: Tue, 03 Jun 2003 23:39:43 -0800
Message-ID: <F001.005A995B.20030603233943@fatcity.com>

For a Hybrid Banking Application , following waits are Observed :- Oracle ver 9.2 (Dedicated Server connections) Solaris 8
M/c SF15K
Application mostly uses Static Queries (i.e. with Bind variables) , though there may be some amount of Literal SQLs too DB Size = 250 GB

Qs How may the following waits be approached ? Qs Since we have just moved to 9.2 , any advisable standard init.ora parameters with 9.2 ? Qs Should CURSOR_SHARING = FORCE or SIMILAR be considered ? Which is better & what may be the Overhead of these on production ?

Shall answer any Clarifications .

Thanks



STATSPACK report for

DB Name DB Id Instance Inst Num Release Cluster Host ------------ ----------- ------------ -------- ----------- ------- ------------ TBASUN 1820705732 tbasun 1 9.2.0.3.0 NO IB15KDB

            Snap Id     Snap Time      Sessions Curs/Sess Comment
            ------- ------------------ -------- --------- -------------------
Begin Snap:      71 03-Jun-03 12:00:05    2,953      53.2
  End Snap:      91 03-Jun-03 13:00:05    3,030      55.2
   Elapsed:               60.00 (mins)

Cache Sizes (end)


               Buffer Cache:       703M      Std Block Size:         8K
           Shared Pool Size:       400M          Log Buffer:     6,144K

Load Profile
~~~~~~~~~~~~                            Per Second       Per Transaction
                                   ---------------       ---------------
                  Redo size:            251,510.31              1,682.23
              Logical reads:             35,458.62                237.17
              Block changes:              1,226.80                  8.21
             Physical reads:              2,391.08                 15.99
            Physical writes:                155.51                  1.04
                 User calls:              8,556.91                 57.23
                     Parses:                495.46                  3.31
                Hard parses:                 71.17                  0.48
                      Sorts:                201.79                  1.35
                     Logons:                  8.80                  0.06
                   Executes:              5,949.80                 39.80
               Transactions:                149.51


% Blocks changed per Read: 3.46 Recursive Call %: 43.86
Rollback per transaction %: 55.51 Rows per Sort: 45.29

Instance Efficiency Percentages (Target 100%)


            Buffer Nowait %:   99.98       Redo NoWait %:   99.99
            Buffer  Hit   %:   93.35    In-memory Sort %:   99.94
            Library Hit   %:   98.14        Soft Parse %:   85.64
         Execute to Parse %:   91.67         Latch Hit %:   98.81
Parse CPU to Parse Elapsd %:    3.56     % Non-Parse CPU:   90.92

 Shared Pool Statistics        Begin   End
                               ------  ------
             Memory Usage %:   93.23   86.67
    % SQL with executions>1: 54.37 75.05
% Memory for SQL w/exec>1: 47.47 70.06

Top 5 Timed Events

~~~~~~~~~~~~~~~~~~                                                     % Total
Event                                               Waits    Time (s) Ela Time
-------------------------------------------- ------------ ----------- --------
library cache pin                                  97,608      95,845    40.95
latch free                                      2,788,119      70,018    29.91
CPU time                                                       25,145    10.74
library cache load lock                            19,686      19,419     8.30
db file sequential read                         6,334,694       6,715     2.87
          -------------------------------------------------------------

          -------------------------------------------------------------
Latch Activity for DB: TBASUN Instance: tbasun Snaps: 71 -91 ->"Get Requests", "Pct Get Miss" and "Avg Slps/Miss" are statistics for   willing-to-wait latch get requests
->"NoWait Requests", "Pct NoWait Miss" are for no-wait latch get requests ->"Pct Misses" for both should be very close to 0.0
                                           Pct    Avg   Wait                 Pct
                              Get          Get   Slps   Time       NoWait NoWait
Latch                       Requests      Miss  /Miss    (s)     Requests   Miss
------------------------ -------------- ------ ------ ------ ------------ ------
library cache                69,587,442    3.3    0.7  53315      663,932   50.5
row cache objects            29,587,406    2.8    0.1   2549      128,096   18.3

Library Cache Activity for DB: TBASUN Instance: tbasun Snaps: 71 -91 ->"Pct Misses" should be very low

                         Get  Pct        Pin        Pct               Invali-
Namespace           Requests  Miss     Requests     Miss     Reloads  dations
--------------- ------------ ------ -------------- ------ ---------- --------
BODY                   3,466   11.3          3,532   17.9        187        0
CLUSTER               12,921    0.1         14,953    0.1          0        0
INDEX                 38,620   19.0         38,618   24.5          8        0
SQL AREA           1,627,354    6.3     26,006,472    0.8    152,116        8
TABLE/PROCEDURE    1,206,367    0.3      1,875,867   15.4    158,738        0
TRIGGER                1,405    0.2          1,713   44.4        542        0
          -------------------------------------------------------------

shared_pool_reserved_size     104857600
shared_pool_size              419430400


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-- 
Author: VIVEK_SHARMA
  INET: VIVEK_SHARMA_at_infosys.com

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Received on Wed Jun 04 2003 - 02:39:43 CDT

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