RES: log buffer size and log file syncs

  Today I was Reading about this topic on old, but amazing blog post from Jonathan Lewis (http://www.jlcomp.demon.co.uk/log_file_writes.html). Maybe you can find what you searching.

  On OracleR Database Performance Tuning Guide documentation from 11gR2 http://docs.oracle.com/cd/E11882_01/server.112/e16638/memory.htm#PFGRF94347

7.4.1 - On most systems, sizing the log buffer larger than 1M does not provide any performance benefit. Increasing the log buffer size does not have any negative implications on performance or recoverability. It merely uses extra memory.

  The official doc said "NO" for your question.   

Best Regards,

Rodrigo Mufalani
Cel.: +55 21 88994817
rodrigo_at_mufalani.com.br
www.mufalani.com.br
twitter: _at_mufalani   

-----Mensagem original-----

De: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] Em nome de CRISLER, JON A
Enviada em: sexta-feira, 27 de abril de 2012 17:37 Para: oracle-l
Assunto: log buffer size and log file syncs

Has anybody run into a case where the log buffer size was too big, and negatively affected log file writes and log file sync waits ?

I have a system that ignores my parameter for 32mb log file size and sets it to 128mb, due to the granule size. The workaround is to lower the granule size so that I can manually set the redo log buffer lower. But I am not sure if this will have any positive affect on log file sync times. Normal I/O for log file writes is fast at 2-4 ms, but log file syncs are bad at 50 to 150 ms.
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http://www.freelists.org/webpage/oracle-l Received on Fri Apr 27 2012 - 16:09:03 CDT