Gathering statistics

Today I just find out a very nice and useful article about gathering statistic in 10g.
Check it out http://structureddata.org/2008/03/26/choosing-an-optimal-stats-gathering-strategy/

DataGuard and ORA-00600

Last week I was asked to configure DataGuard on Oracle 10.2.0.3 64 Bit on RedHat.
Everything was OK, but I forgot to set different "db_unique_name" for both production
and DataGuard databases. I successfully start DataGuard in Maximum performance mode, but when I was trying to start it in more secure mode I bumped into ORA-00600 error - ORA-00600: internal error code, arguments: [krslagap.1], [], [], [], [], [], [], []

I've spend almost one day trying to fix find out why this error appear between mount and open mode.
Finally I rechecked everything I've found a root cause.
So just for your information, always double check all parameters.
BTW - it is better way to inform user about missing or wrong parameter then ORA-00600