Statistics extensions
From: Mladen Gogala <gogala.mladen_at_gmail.com>
Date: Thu, 11 Oct 2012 19:15:08 +0000 (UTC)
Message-ID: <pan.2012.10.11.19.15.08_at_gmail.com>
I had a discussion with Mark Powell on another forum. Just for the record, whenever a function based index is created on 11.2 (I don't have 11.1 available), a statistics extension is created as well. Using "FOR ALL HIDDEN COLUMNS SIZE 254" will collect statistics (height based histograms with 254 buckets) for all such extensions and help the query executions. That is a very little advertised feature of the 11G version.
Date: Thu, 11 Oct 2012 19:15:08 +0000 (UTC)
Message-ID: <pan.2012.10.11.19.15.08_at_gmail.com>
I had a discussion with Mark Powell on another forum. Just for the record, whenever a function based index is created on 11.2 (I don't have 11.1 available), a statistics extension is created as well. Using "FOR ALL HIDDEN COLUMNS SIZE 254" will collect statistics (height based histograms with 254 buckets) for all such extensions and help the query executions. That is a very little advertised feature of the 11G version.
-- Mladen Gogala http://mgogala.freehostia.comReceived on Thu Oct 11 2012 - 21:15:08 CEST