Redo-log Buffer

When does the LGWR writes all redo-enteries to the redo-log buffer?

Questions by megha90

Showing Answers 1 - 14 of 14 Answers

LGWR writes one contiguous portion of the buffer to disk. LGWR writes:
1. A commit record when a user process commits a transaction
Redo log buffers
       – Every three seconds
       – When the redo log buffer is one-third full
       – When a DBWn process writes modified buffers to disk, if necessary

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  • Aug 4th, 2010

LGWR writes to the redo log file in sequential manner under following condition:
When transaction commits
Every 3 seconds
When the redo log buffer cache is is one third full.
When the size of changed records in redo log buffer cache is more than 1 MB.
Before DBWn writes mdofied blocks from database budffer cache to data file.

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Ranjani N

  • Mar 17th, 2011

LGWR writes to the log fine when
1) 1/3 of redolog buffer is full
2) Every 3 secs
3) When log switch occurs
4) Before DBWR writes to the datafiles
5) When the dirty buffers reached the threshold value.
6) When 1 mb of redo has been generated

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  • Dec 27th, 2011

Four conditions when LGWr writes from redo log cache to redo log files

1) 1/3 of redolog buffer is full
2) Every 3 secs
3) For every 1mb collections
4) When Commit occurs

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  • Sep 5th, 2012

lgwr writes from log buffer to log files not to log buffer..


  • Oct 2nd, 2013

This component for Recovery Purpose.Anything changes happen in Dirty buffer like DML operation, ckpt occur from Redo log side, then lgwr write from dirty buffer to redologfiles, data recorded as redo entries and redo transaction.

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  • Feb 6th, 2015

*) Once the user commit, the data are moved to the redologfile
*) Once the one third condition is full.
*) Every 3 secs the data are moved to the redologfilefile.

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  • Feb 9th, 2015

1)at commit
2)when 1/3rd full
3)when there is 1mb of redo
4)every 3 seconds
5)before DBWn writes.

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Mayur Pimpalkar

  • Dec 24th, 2015

Lwgr process writes redo entries to online redolog files not to redobuffer.

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  • Oct 31st, 2017

1) When user hits commit
2) When there is 1/3rd full in redo log cache
3) One every 3 seconds

During this above situation LGWR writes redo log entries into redo log files from redo log cache !!

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