Mar-14

 

27-Mar

LOG_BUFFER size can vary from 8MB to 256MB.  If ASYCHORNUS log transport is configure, it is better to keep log_buffer 128MB or above to enable ‘in memory log’ hits for log transport.  See the note: 951152.1.  See the view x$logbuf_readhist.

 LOG_BUFFER configuration from oracle documentation: http://docs.oracle.com/cd/E11882_01/server.112/e10803/config_db.htm#HABPT4836

 About exadata storage indexes, by Arup :

http://www.oracle.com/technetwork/issue-archive/2011/11-may/o31exadata-354069.html

17-Mar

Oracle Exadata storage indexes intelligence is built into the CELL server to prune the data and reduce the physical I/O.  SI is an In Memory data structure.  For every 1MB data, the maximum and minimum column values for up to 8 columns are stored in storage indexes.  The block will be read by the Cell server only if the column data found in the index.  Placement of a column is automatically identified by the server based on the WHERE clause predicate.    See test cases

http://www.oaktable.net/blog/when-exadata%E2%80%99s-storage-indexes-used

Kerry talks about Exadata offloading – a good one

http://kerryosborne.oracle-guy.com/2010/06/exadata-offload-the-secret-sauce/#more-2531