Background DBWR1 and DBWR0 lock wait event: cache buffers lru chain

Hi all

We have a Test database 10.2.0.1 having

db_writer_processes integer 2
very large integer SGA_MAX_SIZE 1504 M
Whole large SGA_TARGET 1504M

When I check the event of the two background processes is to say DBWR1 and DBWR0 is pending in

latch: cache buffers lru chain

"bdrbd_lcoal > select program session $ v where event =' latch: cache buffers lru chain."

PROGRAM
------------------------------------------------
Oracle@DB (DBW1)
Oracle@DB (DBW0)

When I try to manual control his account more than 4 minutes to complete the command checkpoint
and four session are waiting in case of waiting free buffers.

Please help solve this problem.

Thank you
Jamsher

Edited by: Jamsher February 3, 2011 04:31

Hello

First define the sga_max_size, then sga_target

change the system sga_max_size set = 2000 m; -sga_max_size is not dynamic, closure of the base data, make the changes, and restart the database

ALTER system set sga_target = 1800 m;

You can read the following as well

http://asktom.Oracle.com/pls/asktom/f?p=100:11:0:P11_QUESTION_ID:30011178429375

Published by: jazz81 on February 3, 2011 13:48

Published by: jazz81 on February 3, 2011 13:55

Tags: Database

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                     OR (    udl.action_category = 'U'
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                AND udl.user_id IN (
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                                 BETWEEN TO_DATE ('04/21/2009 17/46/25',
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                                                )
                                     AND TO_DATE ('04/21/2009 17/47/26',
                                                  'MM/DD/YYYY HH24/MI/SS'
                                                 )
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             WHERE udl.action_date BETWEEN TO_DATE ('04/21/2009 17/46/25',
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                                                   )
                                       AND TO_DATE ('04/21/2009 17/47/26',
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Below is the execution plan:
Execution Plan
----------------------------------------------------------
   0      SELECT STATEMENT Optimizer=RULE (Cost=341 Card=3 Bytes=312)
   1    0   SORT (UNIQUE) (Cost=342 Card=3 Bytes=312)
   2    1     UNION-ALL
   3    2       CONCATENATION
   4    3         FILTER
   5    4           NESTED LOOPS (Cost=12 Card=1 Bytes=100)
   6    5             NESTED LOOPS (Cost=11 Card=1 Bytes=94)
   7    6               NESTED LOOPS (Cost=10 Card=1 Bytes=77)
  8    7                 NESTED LOOPS (Cost=8 Card=1 Bytes=52)
   9    8                   TABLE ACCESS (BY INDEX ROWID) OF 'USER_DEL
          IVERY_LOG' (Cost=4 Card=2 Bytes=58)
  10    9                     INDEX (RANGE SCAN) OF 'IE1_USER_DELIVERY
          _LOG' (NON-UNIQUE) (Cost=3 Card=2)
  11    8                   TABLE ACCESS (BY INDEX ROWID) OF 'USER_DEL
          IVERY' (Cost=2 Card=1192563 Bytes=27428949)
  12   11                     INDEX (UNIQUE SCAN) OF 'IDX_PK_INV_USER_
          SD_ID' (UNIQUE) (Cost=1 Card=1192563)
  13    7                 TABLE ACCESS (BY INDEX ROWID) OF 'APPUSER' (
          Cost=2 Card=863102 Bytes=21577550)
  14   13                   INDEX (UNIQUE SCAN) OF 'PK_APPUSER' (UNIQU
          E) (Cost=1 Card=863102)
  15    6               TABLE ACCESS (BY INDEX ROWID) OF 'SITE_DELIVER
          Y' (Cost=1 Card=3494 Bytes=59398)
  16   15                 INDEX (UNIQUE SCAN) OF 'PK_NEW_SITE_DELIVERY
          ' (UNIQUE)
  17    5             TABLE ACCESS (BY INDEX ROWID) OF 'SITE_T' (Cost=
          1 Card=64113 Bytes=384678)
  18   17               INDEX (UNIQUE SCAN) OF 'PK_SITE_T' (UNIQUE)
  19    4           TABLE ACCESS (BY INDEX ROWID) OF 'USER_DELIVERY_LO
          G' (Cost=6 Card=1 Bytes=27)
  20   19             INDEX (RANGE SCAN) OF 'IE1_USER_DELIVERY_LOG' (N
          ON-UNIQUE) (Cost=3 Card=1)
  21    3         FILTER
  22   21           NESTED LOOPS (Cost=12 Card=1 Bytes=100)
  23   22             NESTED LOOPS (Cost=11 Card=1 Bytes=94)
  24   23               NESTED LOOPS (Cost=10 Card=1 Bytes=77)
  25   24                 NESTED LOOPS (Cost=8 Card=1 Bytes=52)
  26   25                   TABLE ACCESS (BY INDEX ROWID) OF 'USER_DEL
          IVERY_LOG' (Cost=4 Card=2 Bytes=58)
  27   26                     INDEX (RANGE SCAN) OF 'IE1_USER_DELIVERY
         _LOG' (NON-UNIQUE) (Cost=3 Card=2)
  28   25                   TABLE ACCESS (BY INDEX ROWID) OF 'USER_DEL
          IVERY' (Cost=2 Card=1192563 Bytes=27428949)
  29   28                     INDEX (UNIQUE SCAN) OF 'IDX_PK_INV_USER_
          SD_ID' (UNIQUE) (Cost=1 Card=1192563)
  30   24                 TABLE ACCESS (BY INDEX ROWID) OF 'APPUSER' (
          Cost=2 Card=863102 Bytes=21577550)
  31   30                   INDEX (UNIQUE SCAN) OF 'PK_APPUSER' (UNIQU
         E) (Cost=1 Card=863102)
  32   23               TABLE ACCESS (BY INDEX ROWID) OF 'SITE_DELIVER
          Y' (Cost=1 Card=3494 Bytes=59398)
  33   32                 INDEX (UNIQUE SCAN) OF 'PK_NEW_SITE_DELIVERY
          ' (UNIQUE)
  34   22             TABLE ACCESS (BY INDEX ROWID) OF 'SITE_T' (Cost=
          1 Card=64113 Bytes=384678)
  35   34               INDEX (UNIQUE SCAN) OF 'PK_SITE_T' (UNIQUE)
  36    2       NESTED LOOPS (Cost=314 Card=1 Bytes=112)
  37   36         NESTED LOOPS (Cost=313 Card=1 Bytes=106)
  38   37           NESTED LOOPS (Cost=312 Card=1 Bytes=89)
  39   38             NESTED LOOPS (Cost=310 Card=1 Bytes=64)
  40   39               NESTED LOOPS (Cost=306 Card=1 Bytes=41)
  41   40                 VIEW OF 'VW_NSO_1' (Cost=302 Card=1 Bytes=22
          )
  42   41                   SORT (GROUP BY) (Cost=302 Card=1 Bytes=35)
  43   42                     NESTED LOOPS (Cost=299 Card=1 Bytes=35)
  44   43                       TABLE ACCESS (FULL) OF 'APPUSER_LOG' (
          Cost=93 Card=1 Bytes=16)
  45   43                       TABLE ACCESS (FULL) OF 'USER_DELIVERY_
          LOG' (Cost=206 Card=73505 Bytes=1396595)
  46   40                 TABLE ACCESS (BY INDEX ROWID) OF 'USER_DELIV
          ERY_LOG' (Cost=4 Card=429251 Bytes=8155769)
  47   46                   INDEX (RANGE SCAN) OF 'IE1_USER_DELIVERY_L
          OG' (NON-UNIQUE) (Cost=3 Card=429251)
  48   39               TABLE ACCESS (BY INDEX ROWID) OF 'USER_DELIVER
         Y' (Cost=4 Card=1192563 Bytes=27428949)
  49   48                 INDEX (RANGE SCAN) OF 'IDX_PK_INV_USER_SD_ID
          ' (UNIQUE) (Cost=3 Card=1192563)
  50   38             TABLE ACCESS (BY INDEX ROWID) OF 'APPUSER' (Cost
          =2 Card=43156 Bytes=1078900)
  51   50               INDEX (UNIQUE SCAN) OF 'PK_APPUSER' (UNIQUE) (
          Cost=1 Card=43156)
  52   51                 NESTED LOOPS (Cost=7 Card=1 Bytes=31)
  53   52                   TABLE ACCESS (BY INDEX ROWID) OF 'USER_DEL
         IVERY_LOG' (Cost=6 Card=1 Bytes=24)
  54   53                     INDEX (RANGE SCAN) OF 'IE1_USER_DELIVERY
          _LOG' (NON-UNIQUE) (Cost=3 Card=1)
  55   52                   TABLE ACCESS (BY INDEX ROWID) OF 'SITE_DEL
          IVERY' (Cost=1 Card=3494 Bytes=24458)
  56   55                     INDEX (UNIQUE SCAN) OF 'PK_NEW_SITE_DELI
          VERY' (UNIQUE)
  57   37           TABLE ACCESS (BY INDEX ROWID) OF 'SITE_DELIVERY' (
          Cost=1 Card=3494 Bytes=59398)
  58   57             INDEX (UNIQUE SCAN) OF 'PK_NEW_SITE_DELIVERY' (U
          NIQUE)
  59   36         TABLE ACCESS (BY INDEX ROWID) OF 'SITE_T' (Cost=1 Ca
          rd=64113 Bytes=384678)
  60   59           INDEX (UNIQUE SCAN) OF 'PK_SITE_T' (UNIQUE)
    For a clear view of the execution plan:
    Plan Table
--------------------------------------------------------------------------------------------------------
| Operation                 |  Name    |  Rows | Bytes|  Cost  | Pstart| Pstop |
--------------------------------------------------------------------------------
| SELECT STATEMENT          |          |     3 |  312 |    341 |       |       |
|  SORT UNIQUE              |          |     3 |  312 |    342 |       |       |
|   UNION-ALL               |          |       |      |        |       |       |
|    CONCATENATION          |          |       |      |        |       |       |
|     FILTER                |          |       |      |        |       |       |
|      NESTED LOOPS         |          |     1 |  100 |     12 |       |       |
|       NESTED LOOPS        |          |     1 |   94 |     11 |       |       |
|        NESTED LOOPS       |          |     1 |   77 |     10 |       |       |
|         NESTED LOOPS      |          |     1 |   52 |      8 |       |       |
|          TABLE ACCESS BY I|USER_DELI |     2 |   58 |      4 |       |       |
|           INDEX RANGE SCAN|IE1_USER_ |     2 |      |      3 |       |       |
|          TABLE ACCESS BY I|USER_DELI |     1M|   26M|      2 |       |       |
|           INDEX UNIQUE SCA|IDX_PK_IN |     1M|      |      1 |       |       |
|         TABLE ACCESS BY IN|APPUSER   |   863K|   20M|      2 |       |       |
|          INDEX UNIQUE SCAN|PK_APPUSE |   863K|      |      1 |       |       |
|        TABLE ACCESS BY IND|SITE_DELI |     3K|   58K|      1 |       |       |
|         INDEX UNIQUE SCAN |PK_NEW_SI |     3K|      |        |       |       |
|       TABLE ACCESS BY INDE|SITE_T    |    64K|  375K|      1 |       |       |
|        INDEX UNIQUE SCAN  |PK_SITE_T |    64K|      |        |       |       |
|      TABLE ACCESS BY INDEX|USER_DELI |     1 |   27 |      6 |       |       |
|       INDEX RANGE SCAN    |IE1_USER_ |     1 |      |      3 |       |       |
|     FILTER                |          |       |      |        |       |       |
|      NESTED LOOPS         |          |     1 |  100 |     12 |       |       |
|       NESTED LOOPS        |          |     1 |   94 |     11 |       |       |
|        NESTED LOOPS       |          |     1 |   77 |     10 |       |       |
|         NESTED LOOPS      |          |     1 |   52 |      8 |       |       |
|          TABLE ACCESS BY I|USER_DELI |     2 |   58 |      4 |       |       |
|           INDEX RANGE SCAN|IE1_USER_ |     2 |      |      3 |       |       |
|          TABLE ACCESS BY I|USER_DELI |     1M|   26M|      2 |       |       |
|           INDEX UNIQUE SCA|IDX_PK_IN |     1M|      |      1 |       |       |
|         TABLE ACCESS BY IN|APPUSER   |   863K|   20M|      2 |       |       |
|          INDEX UNIQUE SCAN|PK_APPUSE |   863K|      |      1 |       |       |
|        TABLE ACCESS BY IND|SITE_DELI |     3K|   58K|      1 |       |       |
|         INDEX UNIQUE SCAN |PK_NEW_SI |     3K|      |        |       |       |
|       TABLE ACCESS BY INDE|SITE_T    |    64K|  375K|      1 |       |       |
|        INDEX UNIQUE SCAN  |PK_SITE_T |    64K|      |        |       |       |
|    NESTED LOOPS           |          |     1 |  112 |    314 |       |       |
|     NESTED LOOPS          |          |     1 |  106 |    313 |       |       |
|      NESTED LOOPS         |          |     1 |   89 |    312 |       |       |
|       NESTED LOOPS        |          |     1 |   64 |    310 |       |       |
|        NESTED LOOPS       |          |     1 |   41 |    306 |       |       |
|         VIEW              |VW_NSO_1  |     1 |   22 |    302 |       |       |
|          SORT GROUP BY    |          |     1 |   35 |    302 |       |       |
|           NESTED LOOPS    |          |     1 |   35 |    299 |       |       |
|            TABLE ACCESS FU|APPUSER_L |     1 |   16 |     93 |       |       |
|            TABLE ACCESS FU|USER_DELI |    73K|    1M|    206 |       |       |
|         TABLE ACCESS BY IN|USER_DELI |   429K|    7M|      4 |       |       |
|          INDEX RANGE SCAN |IE1_USER_ |   429K|      |      3 |       |       |
|        TABLE ACCESS BY IND|USER_DELI |     1M|   26M|      4 |       |       |
|         INDEX RANGE SCAN  |IDX_PK_IN |     1M|      |      3 |       |       |
|       TABLE ACCESS BY INDE|APPUSER   |    43K|    1M|      2 |       |       |
|        INDEX UNIQUE SCAN  |PK_APPUSE |    43K|      |      1 |       |       |
|         NESTED LOOPS      |          |     1 |   31 |      7 |       |       |
|          TABLE ACCESS BY I|USER_DELI |     1 |   24 |      6 |       |       |
|           INDEX RANGE SCAN|IE1_USER_ |     1 |      |      3 |       |       |
|          TABLE ACCESS BY I|SITE_DELI |     3K|   23K|      1 |       |       |
|           INDEX UNIQUE SCA|PK_NEW_SI |     3K|      |        |       |       |
|      TABLE ACCESS BY INDEX|SITE_DELI |     3K|   58K|      1 |       |       |
|       INDEX UNIQUE SCAN   |PK_NEW_SI |     3K|      |        |       |       |
|     TABLE ACCESS BY INDEX |SITE_T    |    64K|  375K|      1 |       |       |
|      INDEX UNIQUE SCAN    |PK_SITE_T |    64K|      |        |       |       |
--------------------------------------------------------------------------------
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    Could someone help me please in the setting of this query, I need to avoid latch and scattered read... .as application knows huge slow...

    -Yasser

    YasserRACDBA wrote:

    Oracle version: 8.1.6.0.0
    The optimizer mode is RULE

    We found all sessions waiting performing this query below:

    (SELECT /*+ORDERED*/

    Even if you run based on rules in general, this query will run based on costs due to the indicator.
    Do you have statistics in place to support the OBC?

    | VIEW |VW_NSO_1 | 1 | 22 | 302 | | |
    | SORT GROUP BY | | 1 | 35 | 302 | | |
    | NESTED LOOPS | | 1 | 35 | 299 | | |
    | TABLE ACCESS FU|APPUSER_L | 1 | 16 | 93 | | |
    | TABLE ACCESS FU|USER_DELI | 73K| 1M| 206 | | |

    This is typical of an unnested "IN" subquery - it looks like the optimiser has unnested your double-level IN subquery finding the maximum action date for a user who has done something in the last minute into a massive group and aggregate (so we've got unnesting and complex view merging all in one - I don't think I've seen that in 8i before).

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    I can't see any reason why the appuser_log table should be subject to cache buffers chains latch problems - if the plan is true than the only thing it suffers is one full scan. However, given the "one row" estimate that comes out of the VW_NOS_1 line, the optimizer is free to do all sorts of silly things as it works through the chain of nested loops, and if the number of rows from the driver is much more than one then the indexed activity against USER_DELIxxx could be huge.

    For example:

    |         TABLE ACCESS BY IN|USER_DELI |   429K|    7M|      4 |       |       |
|          INDEX RANGE SCAN |IE1_USER_ |   429K|      |      3 |       |       |

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    Concerning
    Jonathan Lewis
    http://jonathanlewis.WordPress.com
    http://www.jlcomp.demon.co.UK

    "Science is more than a body of knowledge; It's a way of thinking. "
    Carl Sagan

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    Hello

    the 11.2.0.4 SE on Win 2008

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    Capture.PNG

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    Do you sugest any other question?

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    Hello

    > Can conclude that the most important issue on the database is db file sequential read and should be the subject of an investigation?

    A wait event isn't a problem. It is just a little work of the database and the database is there work wo.

    This is a problem only if you too (in many calls of i/o) or slow (long of IO call duration)

    Your instance has been started just two minutes ago, no? This is not very important. Caches must warm up.

    You need to install Statspack. Read about it ORACLE_HOME/rdbms/admin/spdoc.txt

    Kind regards

    Franck.

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    Hello

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WHERE emp.deptno = dept.deptno;

call   count      cpu    elapsed     disk    query current    rows
---- -------  -------  --------- -------- -------- -------  ------
Parse      1     0.16      0.29         3       13       0       0
Execute    1     0.00      0.00         0        0       0       0
Fetch      1     0.03      0.26         2        2       4      14 
 
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    Concerning
    Evelyne

    For

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    Hi all

    DB: 10.2.0.3 EA
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    Summary:

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----- -------------------- ------------------------------ ------------ ------------------------------
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---------- ----- ------------------------------ ---------- ---------- ------------------- ---------- ---------------
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11:54:40   2     (SELECT ADDR FROM V$PROCESS WHERE PID = 2);

NAME
------------------------------
DBW0
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---------- ----- ------------------------------ ---------- ---------- ------------------- ---------- ---------------
     30315   167 rdbms ipc reply                        55 2147423061 WAITING                      0       0
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12:04:39   2     (SELECT ADDR FROM V$PROCESS WHERE PID = 55);

NAME
------------------------------
RBAL
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EVENT                             BLOCKER
------------------------------ ----------
enq: FP - global fob                  167
contention

12:06:14 xxxx>@sesswait
Enter value for sid: 321

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---------- ----- ------------------------------ ---------- ---------- ------------------- ---------- ---------------
        12   321 enq: FP - global fob           1179648006          0 WAITING                      0           61470
                 contention
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    Published by: joshic on June 30, 2010 04:25

    joshic wrote:
    Hi all
    DB: 10.2.0.3 EA
    Operating system: Solaris 10
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    Looks like Bug 7334426: BACKUP HANG ON A HANG CONDITION BETWEEN DBW AND RBAL

  • TOP 5 WAIT EVENT

    Hello

    the configurations below

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    and the other est--oracle@ora (J003)

    ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
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    DB file sequential read 3 664 522 1 4 528 13.9 user I/O
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    ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

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    RDS

    Published by: user1000000 on September 14, 2009 07:54

    This is the reason why nobody will answer your question probably :-)

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    Hello

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    Suntrupth

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