Multi-threaded LGWR
Date: Tue, 26 Apr 2016 17:10:58 -0400
Message-ID: <571FD962.8060004_at_gmail.com>
Oracle 12c introduced a new feature, namely multi-threaded LGWR. Of course, as it usually happens, you only find out about the new feature when it doesn't work. The problems I encountered are documented in the following support documents:
- 1957710.1
- 21915719.8
I was unable to find any controlling parameter in the documentation,
short of "_use_single_log_writer" which is not really what I want. Does
anyone have any details on that mechanism? How big must LOG_BUFFER be to
start an additional thread? How do threads write? My guess is that they
split the file into peaces and that each thread writes into its own
peace of file. Obviously, there are some issues. In 11G, we saw private
redo strands, now we have multi-threaded log writer. Did anyone do any
research on that? This is a job for systemtap, but I have been
traveling and didn't have much time.
Regards
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Mladen Gogala
Oracle Consultant
http://mgogala.freehostia.com
DISCLAIMER: I am solely responsible for any opinion expressed in this email
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Received on Tue Apr 26 2016 - 23:10:58 CEST