FAQ
Chaos
Oracle continually writes to all copies of the control file. The thing in
your report that jumps out at me is that you have zero (count 'em zero)
physical reads. You must have succeeded in caching all your data in memory.
Congratulations. Also you seem to have few writes. My guess is that
controlfile parallel write is bubbling to the top in the absence of other
waits. Not a bad situation. You may want to look at add other disks in the
future, depending on how important recoverability is to this instance. If
you were to lose this disk, it might be difficult to recover this database.

Dennis Williams
DBA

Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
Sent: Tuesday, August 06, 2002 10:39 AM
To: Multiple recipients of list ORACLE-L
from db-link.

hi, dbas:

I make a statspack report on one of my database and found a wait
event that i did not see quite often.

This is a query intensive database, all 6 tables are snapshot from a
master site and refresh every 1 hour.All other activity is query the tables
and get a lot of data out of the database to middleware.

The following is the statspack,I looked at the Oracle reference and
searched google for control file parallel write, but did not get much
valuable information.

Hope someone here can help me. Does this event really have adverse
impact on database performance, and how to tune it.I have three controlfiles
on the same disk(only one disk in the server).

(One day activity)

Snap Id Snap Time Sessions
------- ------------------ --------
Begin Snap: 1238 06-Aug-02 10:43:39 30
End Snap: 1239 06-Aug-02 21:24:49 30
Elapsed: 641.17 (mins)

Cache Sizes

db_block_buffers: 156672 log_buffer:
2097152

db_block_size: 8192 shared_pool_size:
157286400

Load Profile

--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: DENNIS WILLIAMS
INET: DWILLIAMS_at_LIFETOUCH.COM

Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
San Diego, California -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from). You may
also send the HELP command for other information (like subscribing).

Search Discussions

  • Jared.Still_at_radisys.com at Aug 6, 2002 at 6:28 pm
    He Dennis,

    I can get a 100% hit ratio too!

    See:

    LOGICAL I/O PHYSICAL I/O BLOCK
    USERNAME SYS_ID PROCESS BLOCKS BLOCKS CHANGES IDLE TIME

    HITRATIO

    ---------- ------ ------- ------------ ------------ -----------
    ----------- --------
    JKSTILL 15 21092 1,277,838 311 304

    00:00:00:00 99.98

    OK, so it's only 99.98.

    Here's how:

    drop table c1;
    drop table c2;

    create table c1 as
    select owner, table_name, tablespace_name
    from dba_tables
    where rownum < 10001
    /

    create table c2 as
    select owner, table_name, tablespace_name
    from dba_tables
    where rownum < 10001
    /

    select

    c1.owner, c1.table_name, c1.tablespace_name, c2.owner, c2.table_name, c2.tablespace_name
    from c1, c2
    /

    If I run this every 5 minutes from DBMS_JOB, I can keep my system Hit
    Ratio
    above 98%, and I won't need to do any tuning.;^)

    Jared

    DENNIS WILLIAMS
    Sent by: root_at_fatcity.com
    08/06/2002 09:13 AM
    Please respond to ORACLE-L



    To: Multiple recipients of list ORACLE-L
    cc:
    Subject: RE: wait event:controlfile parallel write and sql*net more data f

    Chaos
    Oracle continually writes to all copies of the control file. The thing
    in
    your report that jumps out at me is that you have zero (count 'em zero)
    physical reads. You must have succeeded in caching all your data in
    memory.
    Congratulations. Also you seem to have few writes. My guess is that
    controlfile parallel write is bubbling to the top in the absence of other
    waits. Not a bad situation. You may want to look at add other disks in the
    future, depending on how important recoverability is to this instance. If
    you were to lose this disk, it might be difficult to recover this
    database.

    Dennis Williams
    DBA

    Lifetouch, Inc.
    dwilliams_at_lifetouch.com

    -----Original Message-----
    Sent: Tuesday, August 06, 2002 10:39 AM
    To: Multiple recipients of list ORACLE-L
    from db-link.

    hi, dbas:

    I make a statspack report on one of my database and found a wait
    event that i did not see quite often.

    This is a query intensive database, all 6 tables are snapshot from
    a
    master site and refresh every 1 hour.All other activity is query the
    tables
    and get a lot of data out of the database to middleware.

    The following is the statspack,I looked at the Oracle reference
    and
    searched google for control file parallel write, but did not get much
    valuable information.

    Hope someone here can help me. Does this event really have adverse
    impact on database performance, and how to tune it.I have three
    controlfiles
    on the same disk(only one disk in the server).

    (One day activity)

    Snap Id Snap Time Sessions
    ------- ------------------ --------
    Begin Snap: 1238 06-Aug-02 10:43:39 30
    End Snap: 1239 06-Aug-02 21:24:49 30
    Elapsed: 641.17 (mins)

    Cache Sizes

    db_block_buffers: 156672 log_buffer:
    2097152

    db_block_size: 8192 shared_pool_size:
    157286400

    Load Profile

    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.com
    --
    Author: DENNIS WILLIAMS
    INET: DWILLIAMS_at_LIFETOUCH.COM

    Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
    San Diego, California -- Public Internet access / Mailing Lists
    --------------------------------------------------------------------
    To REMOVE yourself from this mailing list, send an E-Mail message
    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
    the message BODY, include a line containing: UNSUB ORACLE-L
    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).

    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.com
    --
    Author:
    INET: Jared.Still_at_radisys.com

    Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
    San Diego, California -- Public Internet access / Mailing Lists
    --------------------------------------------------------------------
    To REMOVE yourself from this mailing list, send an E-Mail message
    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
    the message BODY, include a line containing: UNSUB ORACLE-L
    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).

Related Discussions

Discussion Navigation
viewthread | post
Discussion Overview
grouporacle-l @
categoriesoracle
postedAug 6, '02 at 4:13p
activeAug 6, '02 at 6:28p
posts2
users2
websiteoracle.com

People

Translate

site design / logo © 2022 Grokbase