Well spotted. I was looking for things to do with dates or truncates when I checked the fix controls and parameters and missed that one completely. (There's a lovely parameter including the word "datefold" that looked very promising but obviously turned out to be irrelevant.) Regards Jonathan Lewis http://jonathanlewis.wordpress.com @jloracle ________________________________ From: Velikikh Mikhail [mvelikikh@xxxxxxxxx] Sent: 20 April 2014 05:01 To: Jonathan Lewis Cc: Mohamed Houri; oracle-l@xxxxxxxxxxxxx Subject: Re: Function-based indexes and trunc() Hi, Seems like this enhancement introduced in 11.2.0.2 with fix_control 9263333. SQL> exec print_table( 'select * from v$system_fix_control where bugno=9263333') BUGNO : 9263333 VALUE : 1 SQL_FEATURE : QKSFM_CBO_9263333 DESCRIPTION : generate transitive predicates for virtual column expressions OPTIMIZER_FEATURE_ENABLE : 11.2.0.2 EVENT : 0 IS_DEFAULT : 1 -----------------