Re: How does LNS works?

[Aravindkumar Annamalai]

Hi,

 

Does LNS read Redo records from Redolog Buffer or Redolog File when
LGWR Sync and Async is being used ?

 

 

Regards,

-Arvind

[ddf]

On Oct 15, 2:37 am, Aravindkumar Annamalai

The LGWR process does not wait for each network I/O to complete when
configured to use asynch writes. This is made possible by use of an
intermediate process, known as a Log Writer Network Server Process
(LNS), which performs the actual network I/O and waits for each
network I/O to complete. Each LNS has a configurable buffer used to
accept outbound redo data from the LGWR process. Specifying the size
in 512 byte blocks on the ASYNC attribute in the archivelog
destination parameter is how this is configured. For example,
ASYNC=2048 indicates a 1MB buffer. As long as the LNS process is able
to empty this buffer faster than the LGWR can fill it, the LGWR
process will never stall. If the LNS cannot keep up, then the buffer
will become full and the LGWR process will stall until either
sufficient buffer space is freed up by a successful network
transmission or a network timeout occurs.


David Fitzjarrell