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:

 About exadata storage indexes, by Arup :


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

Kerry talks about Exadata offloading – a good one



  1. No comments yet.
  1. No trackbacks yet.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: