Mladen,
Larger histograms -- uses the same 254 columns by default
New calculation for clustering_factor -- uses the old mechanism
(table_cached_blocks = 1) by default
New type of histograms: you still get Top-N and Hybrid histograms with OFE=
11.2.0.4 if you have preference approximate_ndv = true (though you can disable
them). But Frequency and Top-N give you much better accuracy virtually free of
ANY cost (in 12.1.0.2) and Hybrid give you better accuracy for no increase over
the 11g cost - the main problem is that frequency and top-N histograms may be
based on a small sample size if you set OFE=11.2.0.4
Regards
Jonathan Lewis
________________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx <oracle-l-bounce@xxxxxxxxxxxxx> on behalf
of Mladen Gogala <gogala.mladen@xxxxxxxxx>
Sent: 01 May 2017 13:22
To: Stefan Koehler
Cc: oracle-l@xxxxxxxxxxxxx
Subject: Re: Query Performance with params
Well, there are several more changes you didn't mention: new type of
histograms, much larger histograms and a new way to calculate clustering
factor.
--
//www.freelists.org/webpage/oracle-l
