Simpler Navigation coming for Servers and Operating Systems
Coming soon: a much simpler Servers and Operating Systems section of the Community. We will combine many of the older boards, and you won't have to click through so many levels to get at the information you need. If you are looking for an older board and do not find it, check the consolidated boards, as the posts are still there.
cancel
Showing results for 
Search instead for 
Did you mean: 

Discussion

sachin kapse
Occasional Visitor

Discussion

What are redo log files & latches in oracle
4 REPLIES
HGN
Honored Contributor

Re: Discussion

Hi

Looks like you have posted in the wrong forum, this is a Unix forum (HPUX), someone might have details you can also try oracle discussion.

Rgds

HGN
Peter Godron
Honored Contributor

Re: Discussion

Hi,
In short:

redo logs are files where uncommited changes are written as part of a two-phase commit process i.e. changes are held there until the commit is issued.


latches are holds of data-structures in the SGA whilst the process is using them.

For further reading on latches:
http://oracle.ittoolbox.com/documents/peer-publishing/latches-and-latch-contention-2371
Sean Dale
Trusted Contributor

Re: Discussion

Just in case you were wondering, once redo log rotations are full, they are archived. That is what archivelogs are. Archivelogs are used to restore/undo information, if needed. They are also transferred to standby databases to keep them in sync if you are using dataguard.
Live life everyday
Jonathan Fife
Honored Contributor

Re: Discussion

Hi,

A follow up to Peter's response -- the redo logs actually hold both committed and uncommitted data. If you lose a group of un-archived redo logs you will almost certainly lose committed data, so it is important to multiplex them across physical locations.
Decay is inherent in all compounded things. Strive on with diligence