Salut a tous,
ma base de données souffre de gros rallentissement en ce moment et j'ai donc généré ce rapport STATSPACK.
Maintenant et bien je suis un peu embeter pour en tirer des actions

Les evenements qui consomment le + de temps sont "db file scattered read" et "enqueue". Mais ça veut dire quoi pour le comment de mortels ?

MErci de votre aide dans cette analyze.


Code : Sélectionner tout - Visualiser dans une fenêtre à part
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STATSPACK report for
 
DB Name         DB Id    Instance     Inst Num Release     Cluster Host
------------ ----------- ------------ -------- ----------- ------- ------------
PROD            48050787 prod                1 9.2.0.8.0   NO      ORA_002
 
              Snap Id     Snap Time      Sessions Curs/Sess Comment
            --------- ------------------ -------- --------- -------------------
Begin Snap:        31 05-Feb-09 13:15:45      195       8.1
  End Snap:        33 05-Feb-09 14:35:43      210       8.5
   Elapsed:               79.97 (mins)
 
Cache Sizes (end)
~~~~~~~~~~~~~~~~~
               Buffer Cache:     1,800M      Std Block Size:          8K
           Shared Pool Size:       464M          Log Buffer:          8K
 
Load Profile
~~~~~~~~~~~~                            Per Second       Per Transaction
                                   ---------------       ---------------
                  Redo size:              6,252.18             10,972.18
              Logical reads:             28,730.26             50,419.83
              Block changes:                 40.03                 70.26
             Physical reads:              1,017.76              1,786.10
            Physical writes:                 64.53                113.25
                 User calls:                 32.07                 56.28
                     Parses:                 18.59                 32.62
                Hard parses:                  3.98                  6.98
                      Sorts:                  5.24                  9.19
                     Logons:                  0.05                  0.09
                   Executes:                196.19                344.31
               Transactions:                  0.57
 
  % Blocks changed per Read:    0.14    Recursive Call %:     88.66
 Rollback per transaction %:   39.10       Rows per Sort:   2028.73
 
Instance Efficiency Percentages (Target 100%)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            Buffer Nowait %:  100.00       Redo NoWait %:     99.98
            Buffer  Hit   %:   96.67    In-memory Sort %:     98.72
            Library Hit   %:   97.40        Soft Parse %:     78.61
         Execute to Parse %:   90.53         Latch Hit %:     99.97
Parse CPU to Parse Elapsd %:   99.21     % Non-Parse CPU:     91.40
 
 Shared Pool Statistics        Begin   End
                               ------  ------
             Memory Usage %:   83.80   84.33
    % SQL with executions>1:   18.19   16.40
  % Memory for SQL w/exec>1:   30.03   23.62
 
Top 5 Timed Events
~~~~~~~~~~~~~~~~~~                                                     % Total
Event                                               Waits    Time (s) Ela Time
-------------------------------------------- ------------ ----------- --------
db file scattered read                            919,336       3,120    44.98
enqueue                                               532       1,590    22.92
CPU time                                                        1,557    22.45
db file sequential read                            51,195         226     3.25
direct path read                                   34,173         187     2.69
          -------------------------------------------------------------
Wait Events for DB: PROD  Instance: prod  Snaps: 31 -33
-> s  - second
-> cs - centisecond -     100th of a second
-> ms - millisecond -    1000th of a second
-> us - microsecond - 1000000th of a second
-> ordered by wait time desc, waits desc (idle events last)
 
                                                                   Avg
                                                     Total Wait   wait    Waits
Event                               Waits   Timeouts   Time (s)   (ms)     /txn
---------------------------- ------------ ---------- ---------- ------ --------
db file scattered read            919,336          0      3,120      3    336.3
enqueue                               532        528      1,590   2988      0.2
db file sequential read            51,195          0        226      4     18.7
direct path read                   34,173          0        187      5     12.5
log file sync                       2,891          0         92     32      1.1
db file parallel write                593          0         64    108      0.2
control file parallel write         1,678          0         63     38      0.6
direct path write                     680          0          8     12      0.2
log buffer space                      140          0          8     55      0.1
direct path read (lob)              1,011          0          7      7      0.4
control file sequential read        2,106          0          5      2      0.8
buffer busy waits                     556          0          3      5      0.2
log file switch completion             13          0          3    229      0.0
direct path write (lob)                27          0          2     57      0.0
SQL*Net more data to client        16,662          0          1      0      6.1
log file sequential read               84          0          1      8      0.0
log file single write                  36          0          1     16      0.0
log file parallel write             4,140          0          0      0      1.5
latch free                            129         85          0      2      0.0
library cache pin                       4          0          0     12      0.0
SQL*Net break/reset to clien           38          0          0      0      0.0
LGWR wait for redo copy                29          0          0      0      0.0
row cache lock                          3          0          0      0      0.0
async disk IO                          18          0          0      0      0.0
virtual circuit status            126,377        146     13,587    108     46.2
SQL*Net message from client       127,566          0         73      1     46.7
SQL*Net message to client         127,675          0          0      0     46.7
SQL*Net more data from clien        1,363          0          0      0      0.5
          -------------------------------------------------------------
Background Wait Events for DB: PROD  Instance: prod  Snaps: 31 -33
-> ordered by wait time desc, waits desc (idle events last)
 
                                                                   Avg
                                                     Total Wait   wait    Waits
Event                               Waits   Timeouts   Time (s)   (ms)     /txn
---------------------------- ------------ ---------- ---------- ------ --------
db file parallel write                593          0         64    108      0.2
control file parallel write         1,678          0         63     38      0.6
control file sequential read        2,002          0          5      3      0.7
log file switch completion              3          0          1    335      0.0
log buffer space                       35          0          1     24      0.0
log file sequential read               84          0          1      8      0.0
log file single write                  36          0          1     16      0.0
direct path write                      36          0          0     11      0.0
log file parallel write             4,140          0          0      0      1.5
direct path read                       36          0          0      5      0.0
rdbms ipc reply                        47          0          0      0      0.0
LGWR wait for redo copy                29          0          0      0      0.0
async disk IO                          18          0          0      0      0.0
buffer busy waits                       1          0          0      0      0.0
rdbms ipc message                   9,963      4,801     28,520   2863      3.6
smon timer                            299          1      4,841  16191      0.1
pmon timer                          1,677      1,594      4,747   2831      0.6
          -------------------------------------------------------------
 
          -------------------------------------------------------------
Instance Activity Stats for DB: PROD  Instance: prod  Snaps: 31 -33
 
Statistic                                      Total     per Second    per Trans
--------------------------------- ------------------ -------------- ------------
CPU used by this session                     155,700           32.5         57.0
CPU used when call started                   155,602           32.4         56.9
CR blocks created                             12,115            2.5          4.4
DBWR checkpoint buffers written                6,313            1.3          2.3
DBWR checkpoints                                   6            0.0          0.0
DBWR transaction table writes                     64            0.0          0.0
DBWR undo block writes                         1,459            0.3          0.5
SQL*Net roundtrips to/from client            253,690           52.9         92.8
active txn count during cleanout             118,970           24.8         43.5
background checkpoints completed                   6            0.0          0.0
background checkpoints started                     6            0.0          0.0
background timeouts                            5,830            1.2          2.1
branch node splits                                 0            0.0          0.0
buffer is not pinned count                90,786,459       18,921.7     33,206.5
buffer is pinned count                    73,412,604       15,300.7     26,851.7
bytes received via SQL*Net from c         25,637,028        5,343.3      9,377.1
calls to get snapshot scn: kcmgss          1,297,984          270.5        474.8
calls to kcmgas                               24,190            5.0          8.9
calls to kcmgcs                                  728            0.2          0.3
change write time                                890            0.2          0.3
cleanout - number of ktugct calls             16,097            3.4          5.9
cleanouts and rollbacks - consist             11,670            2.4          4.3
cleanouts only - consistent read                  28            0.0          0.0
cluster key scan block gets                   30,856            6.4         11.3
cluster key scans                             10,790            2.3          4.0
commit cleanout failures: buffer                   6            0.0          0.0
commit cleanout failures: callbac                  4            0.0          0.0
commit cleanout failures: cannot                   1            0.0          0.0
commit cleanouts                              21,709            4.5          7.9
commit cleanouts successfully com             21,698            4.5          7.9
commit txn count during cleanout               1,272            0.3          0.5
consistent changes                           460,340           95.9        168.4
consistent gets                          137,639,843       28,686.9     50,343.8
consistent gets - examination             11,293,517        2,353.8      4,130.8
cursor authentications                         2,392            0.5          0.9
data blocks consistent reads - un            459,516           95.8        168.1
db block changes                             192,086           40.0         70.3
db block gets                                210,438           43.9         77.0
deferred (CURRENT) block cleanout             11,432            2.4          4.2
dirty buffers inspected                            0            0.0          0.0
enqueue conversions                              887            0.2          0.3
enqueue deadlocks                                  1            0.0          0.0
enqueue releases                              60,287           12.6         22.1
enqueue requests                              60,293           12.6         22.1
enqueue timeouts                                   4            0.0          0.0
enqueue waits                                      5            0.0          0.0
execute count                                941,330          196.2        344.3
failed probes on index block recl                  6            0.0          0.0
free buffer inspected                            312            0.1          0.1
free buffer requested                      4,606,330          960.1      1,684.8
hot buffers moved to head of LRU              25,235            5.3          9.2
immediate (CR) block cleanout app             11,698            2.4          4.3
immediate (CURRENT) block cleanou              1,990            0.4          0.7
index crx upgrade (positioned)                22,082            4.6          8.1
index fast full scans (full)                     634            0.1          0.2
index fetch by key                         4,916,543        1,024.7      1,798.3
Instance Activity Stats for DB: PROD  Instance: prod  Snaps: 31 -33
 
Statistic                                      Total     per Second    per Trans
--------------------------------- ------------------ -------------- ------------
index scans kdiixs1                       48,713,855       10,153.0     17,817.8
leaf node 90-10 splits                            44            0.0          0.0
leaf node splits                                 153            0.0          0.1
logons cumulative                                257            0.1          0.1
messages received                              5,604            1.2          2.1
messages sent                                  5,604            1.2          2.1
no buffer to keep pinned count                     0            0.0          0.0
no work - consistent read gets           125,973,953       26,255.5     46,076.8
opened cursors cumulative                     86,427           18.0         31.6
parse count (failures)                             0            0.0          0.0
parse count (hard)                            19,074            4.0          7.0
parse count (total)                           89,191           18.6         32.6
parse time cpu                                13,388            2.8          4.9
parse time elapsed                            13,495            2.8          4.9
physical reads                             4,883,189        1,017.8      1,786.1
physical reads direct                        289,521           60.3        105.9
physical reads direct (lob)                    2,554            0.5          0.9
physical writes                              309,619           64.5        113.3
physical writes direct                       303,120           63.2        110.9
physical writes direct (lob)                     186            0.0          0.1
physical writes non checkpoint               305,066           63.6        111.6
pinned buffers inspected                         284            0.1          0.1
prefetched blocks                          3,620,564          754.6      1,324.3
process last non-idle time                     4,815            1.0          1.8
recursive calls                            1,202,721          250.7        439.9
recursive cpu usage                           51,775           10.8         18.9
redo blocks written                           62,012           12.9         22.7
redo buffer allocation retries                   155            0.0          0.1
redo entries                                 103,719           21.6         37.9
redo log space requests                           17            0.0          0.0
redo log space wait time                         298            0.1          0.1
redo size                                 29,997,936        6,252.2     10,972.2
redo synch time                                9,167            1.9          3.4
redo synch writes                              2,891            0.6          1.1
redo wastage                               1,000,616          208.6        366.0
redo write time                               13,211            2.8          4.8
redo writer latching time                          0            0.0          0.0
redo writes                                    4,143            0.9          1.5
rollback changes - undo records a              7,478            1.6          2.7
rollbacks only - consistent read                 517            0.1          0.2
rows fetched via callback                  4,196,931          874.7      1,535.1
session connect time                               0            0.0          0.0
session logical reads                    137,847,808       28,730.3     50,419.8
session pga memory                         4,254,380          886.7      1,556.1
session pga memory max                    25,607,936        5,337.2      9,366.5
session uga memory                         4,654,652          970.1      1,702.5
session uga memory max                    38,878,016        8,103.0     14,220.2
shared hash latch upgrades - no w             32,039            6.7         11.7
sorts (disk)                                     322            0.1          0.1
sorts (memory)                                24,814            5.2          9.1
sorts (rows)                              50,994,119       10,628.2     18,651.8
summed dirty queue length                          0            0.0          0.0
switch current to new buffer                   1,353            0.3          0.5
table fetch by rowid                      46,354,793        9,661.3     16,954.9
table fetch continued row                      4,444            0.9          1.6
table scan blocks gotten                  19,475,278        4,059.0      7,123.4
Instance Activity Stats for DB: PROD  Instance: prod  Snaps: 31 -33
 
Statistic                                      Total     per Second    per Trans
--------------------------------- ------------------ -------------- ------------
table scan rows gotten                 1,169,990,349      243,849.6    427,940.9
table scans (long tables)                      2,743            0.6          1.0
table scans (short tables)                    51,683           10.8         18.9
transaction rollbacks                            108            0.0          0.0
user calls                                   153,874           32.1         56.3
user commits                                   1,665            0.4          0.6
user rollbacks                                 1,069            0.2          0.4
workarea executions - multipass                   12            0.0          0.0
workarea executions - onepass                    197            0.0          0.1
workarea executions - optimal                 35,507            7.4         13.0
write clones created in backgroun                  0            0.0          0.0
write clones created in foregroun                 28            0.0          0.0
 
          -------------------------------------------------------------
PGA Aggr Target Stats for DB: PROD  Instance: prod  Snaps: 31 -33
-> B: Begin snap   E: End snap (rows dentified with B or E contain data
   which is absolute i.e. not diffed over the interval)
-> PGA cache hit % - percentage of W/A (WorkArea) data processed only in-memory
-> Auto PGA Target - actual workarea memory target
-> W/A PGA Used    - amount of memory used for all Workareas (manual + auto)
-> %PGA W/A Mem    - percentage of PGA memory allocated to workareas
-> %Auto W/A Mem   - percentage of workarea memory controlled by Auto Mem Mgmt
-> %Man W/A Mem    - percentage of workarea memory under manual control
 
PGA Cache Hit % W/A MB Processed Extra W/A MB Read/Written
--------------- ---------------- -------------------------
           89.6           15,018                     1,738
 
                                             %PGA  %Auto   %Man
  PGA Aggr  Auto PGA   PGA Mem    W/A PGA    W/A    W/A    W/A   Global Mem
  Target(M) Target(M)  Alloc(M)   Used(M)    Mem    Mem    Mem    Bound(K)
- --------- --------- ---------- ---------- ------ ------ ------ ----------
B       150       119       20.9        0.8    3.7     .0  100.0      7,680
E       150       120       22.9        0.9    3.8     .0  100.0      7,680
          -------------------------------------------------------------
 
PGA Aggr Target Histogram for DB: PROD  Instance: prod  Snaps: 31 -33
-> Optimal Executions are purely in-memory operations
 
    Low    High
Optimal Optimal    Total Execs Optimal Execs 1-Pass Execs M-Pass Execs
------- ------- -------------- ------------- ------------ ------------
     2K      4K         18,371        18,371            0            0
     4K      8K            611           611            0            0
     8K     16K            155           155            0            0
    16K     32K            615           615            0            0
    32K     64K            816           816            0            0
    64K    128K            163           163            0            0
   128K    256K            272           272            0            0
   256K    512K             68            68            0            0
   512K   1024K         14,088        14,086            2            0
     1M      2M            111           110            1            0
     2M      4M            307           217           78           12
     4M      8M              2             2            0            0
     8M     16M            116             0          116            0
          -------------------------------------------------------------
 
PGA Memory Advisory for DB: PROD  Instance: prod  End Snap: 33
-> When using Auto Memory Mgmt, minimally choose a pga_aggregate_target value
   where Estd PGA Overalloc Count is 0
 
                                       Estd Extra    Estd PGA   Estd PGA
PGA Target    Size           W/A MB   W/A MB Read/      Cache  Overalloc
  Est (MB)   Factr        Processed Written to Disk     Hit %      Count
---------- ------- ---------------- ---------------- -------- ----------
        19     0.1            766.6          1,294.3     37.0         76
        38     0.3            766.6            561.5     58.0          5
        75     0.5            766.6            287.1     73.0          0
       113     0.8            766.6            247.2     76.0          0
       150     1.0            766.6            125.6     86.0          0
       180     1.2            766.6             81.0     90.0          0
       210     1.4            766.6             51.0     94.0          0
       240     1.6            766.6             39.8     95.0          0
       270     1.8            766.6              0.0    100.0          0
       300     2.0            766.6              0.0    100.0          0
       450     3.0            766.6              0.0    100.0          0
       600     4.0            766.6              0.0    100.0          0
       900     6.0            766.6              0.0    100.0          0
     1,200     8.0            766.6              0.0    100.0          0
          -------------------------------------------------------------
Enqueue activity for DB: PROD  Instance: prod  Snaps: 31 -33
-> Enqueue stats gathered prior to 9i should not be compared with 9i data
-> ordered by Wait Time desc, Waits desc
 
                                                        Avg Wt         Wait
Eq     Requests    Succ Gets Failed Gets       Waits   Time (ms)     Time (s)
-- ------------ ------------ ----------- ----------- ------------- ------------
TM       20,239       20,235           2           2    607,320.50        1,215
TX       10,741       10,740           0           3     11,510.33           35
          -------------------------------------------------------------