Log_buffer

[Sonia]

Hi,
How to size log buffer cache....

The parameter log_buffer doesn't seem to be have any effect on the size on the log buffer cache...
Wht for is this parameter log_buffer is ?


regards
sonia

[grjohnson]

What Oracle version, because on 8.1.7 is does... and I'm pretty sure it's the same for 9.2.

[SANJAY_G]

I think it is same from Oracle 7 to 9i.
You may be missing something, make sure you are editing the correct init.ora file.

Sanjay

[Sonia]

hi,
it is 8.1.7...
Wht does this parameter specify...log_buffer
and why this value shoud be a multiple of 512k...

[sona]

LOG_BUFFER specifies the amount of memory, in bytes, that Oracle uses when buffering redo entries to a redo log file. Redo log entries contain a record of the changes that have been made to the database block buffers. The LGWR process writes redo log entries from the log buffer to a redo log file.

In general, larger values for LOG_BUFFER reduce redo log file I/O, particularly if transactions are long or numerous.

If the 'redo log space requests' statistic in V$SYSSTAT is non-zero, you should increase LOG BUFFER.

SELECT name, value
FROM V$SYSSTAT where name ='redo log space requests';

A good starting point for the log_buffer is 64K, there is generally no advantage in making the log_buffer larger than 1 Mb.

VALUE: Maximum is 512 KB or 128 KB * CPU_COUNT, whichever is greater.




[Edited by sona on 08-22-2002 at 01:29 AM]

[asharsidd]

I don't know why its not effecting your log buffer size..the only parameter is LOG_BUFFER and be sure to edit the correct init.ora file.

[pando]

if you are using 9.2 and your database creation is all by default then most probably is you are using spfile so editing init.ora is not enough