Re: 11gR2 rman compression algorithms

From: Yong Huang <yong321_at_yahoo.com>
Date: Fri, 5 Sep 2014 08:31:14 -0700
Message-ID: <1409931074.42264.YahooMailNeo_at_web184801.mail.gq1.yahoo.com>

Maybe we can guess at some algorithms from what's in v$rman_compression_algorithm.

ALGORITHM_ ALGORITHM_DESCRIPTION
---------- -------------------------------------------

BZIP2      good compression ratio
BASIC      good compression ratio
LOW        maximum possible compression speed
ZLIB       balance between speed and compression ratio
MEDIUM     balance between speed and compression ratio
HIGH       maximum possible compression ratio

It's possible Basic means BZIP2 because they have the same description, and Medium means ZLIB.

From x$ksppi, parameter _backup_lzo_size means "specifies buffer size for LOW compression" so we know Low means LZO.

The only remaining one we don't know is High.

Of course, this is not official answer. The guess could be wrong.
--

http://www.freelists.org/webpage/oracle-l Received on Fri Sep 05 2014 - 17:31:14 CEST