FAQ
I'm having a big problem my database is stopping for like 20 seconds because
it can not write to it redo log

As it looks it seems to be full, but this should not be. The acriver is
archiving group 3 and the lgwr wants to write to group 1. Is there anyone
how has had this problem before.
Or who might have some tips on where or how i can solve this.

I have looked for I/o problme but this does not seen to be the problem

--
Vincent Verpoort,.-~`"'~-.,_,.-~`"'~-.,_,.-~`"'~-.,_,.-~`"'~-.,_,.-~`"'~-.,_
Communiceren is begrepen worden
^*<-._,.->*^*<-._,.->*^*<-._,.->*^*<-._,.->*^*<-._,.->*^*<-.

--
http://www.freelists.org/webpage/oracle-l

Search Discussions

  • Hemant K Chitale at Jun 19, 2006 at 3:10 pm
    Are you identifying the fact that ARCH is archiving Group3 but the LGWR is
    attempting to write to Group1
    from some messages in the alert.log ?
    Do those messages say "checkpoint not complete" ?

    When LGWR finishes writing to a Logfile (eg Group3), it does three things :

    signals ARCH to start archiving it
    signals DBWR to execute a database checkpoint
    checks if the next Logfile (Group1) is available for writing and, if
    so, overwrrites it,
    if not, starts waiting

    It could be so happening that either even if a) has completed, b) has not
    yet completed,
    so LGWR will not overwrite the Logfile.

    Solutions :

    I/O performance tuning / load balancing to increase the speed of
    the checkpoints
    (eg even actually reducing the db_block_buffers ! -- to reduce the number
    of dirty buffers
    to be written)
    add more log files so that LGWR does not have to wrap from Group3 to
    Group1 but
    can go to Group4, Group5, Group6 before it comes back to Group1, by which time
    DBWR should have finished the checkpoint
    create larger log files so that LGWR spends more time inside each
    Logfile before
    attempting to switch to the next one

    each has it's own pros and cons ! (eg if you have a Standby Database, you
    would *want*
    more frequent Log Switches (eg smaller log files or a job issuing "alter
    system archive log current"))

    Hemant
    At 10:47 PM Monday, Vincent verpoort wrote:
    I'm having a big problem my database is stopping for like 20 seconds
    because it can not write to it redo log

    As it looks it seems to be full, but this should not be. The acriver is
    archiving group 3 and the lgwr wants to write to group 1. Is there anyone
    how has had this problem before.
    Or who might have some tips on where or how i can solve this.

    I have looked for I/o problme but this does not seen to be the problem



    --
    Vincent Verpoort

    ,.-~`"'~-.,_,.-~`"'~-.,_,.-~`"'~-.,_,.-~`"'~-.,_,.-~`"'~-.,_
    Communiceren is begrepen worden
    ^*<-._,.->*^*<-._,.->*^*<-._,.->*^*<-._,.->*^*<-._,.->*^*<-.
    Hemant K Chitale
    http://web.singnet.com.sg/~hkchital
  • Alex Gorbachev at Jun 19, 2006 at 6:59 pm
    V$LOG is your friend. There are two interesting columns to you:
    - one reflects that there redo log needs to be archived (than ARC
    performace is bad).
    - another one reflects that redo log is required for crash recovery -
    and you need to look at DBWR performance and your checkpointing.

    2006/6/19, Vincent verpoort :
    I'm having a big problem my database is stopping for like 20 seconds because
    it can not write to it redo log

    As it looks it seems to be full, but this should not be. The acriver is
    archiving group 3 and the lgwr wants to write to group 1. Is there anyone
    how has had this problem before.
    Or who might have some tips on where or how i can solve this.

    I have looked for I/o problme but this does not seen to be the problem



    --
    Vincent Verpoort


    ,.-~`"'~-.,_,.-~`"'~-.,_,.-~`"'~-.,_,.-~`"'~-.,_,.-~`"'~-.,_
    Communiceren is begrepen worden
    ^*<-._,.->*^*<-._,.->*^*<-._,.->*^*<-._,.->*^*<-._,.->*^*<-.
    --
    Best regards,
    Alex Gorbachev

    http://blog.oracloid.com
    --
    http://www.freelists.org/webpage/oracle-l

Related Discussions

Discussion Navigation
viewthread | post
Discussion Overview
grouporacle-l @
categoriesoracle
postedJun 19, '06 at 2:47p
activeJun 19, '06 at 6:59p
posts3
users3
websiteoracle.com

People

Translate

site design / logo © 2022 Grokbase