Merge 'trunk' into 'sybase'

r9213@hlagh (orig r7350):  abraxxa | 2009-08-20 09:07:29 -0400
pod patch for 'Tracing SQL' examples

r9216@hlagh (orig r7353):  spb | 2009-08-20 13:53:02 -0400
Minor fix to the previous doc patch
r9217@hlagh (orig r7354):  frew | 2009-08-20 17:54:04 -0400
add some basic guards to get rid of warnings
r9221@hlagh (orig r7358):  ribasushi | 2009-08-21 05:18:43 -0400
Because prefetch uses the cache system, it is not possible to set HRI on a prefetched rs without upsetting the tests - don't compare