On Thu, Aug 16, 2012 at 4:40 PM, Heikki Linnakangas <
heikki.linnakan...@enterprisedb.com> wrote:

> On 15.08.2012 11:34, Alexander Korotkov wrote:
>> Ok, we've to decide if we need "standard" histogram. In some cases it can
>> be used for more accurate estimation of<  and>  operators.
>> But I think it is not so important. So, we can replace "standard"
>> histogram
>> with histograms of lower and upper bounds?
> Yeah, I think that makes more sense. The lower bound histogram is still
> useful for < and > operators, just not as accurate if there are lots of
> values with the same lower bound but different upper bound.

New version of patch.
* Collect new stakind STATISTIC_KIND_BOUNDS_HISTOGRAM, which is lower and
upper bounds histograms combined into single ranges array, instead
* Selectivity estimations for >, >=, <, <=, <<, >>, &<, &> using this

With best regards,
Alexander Korotkov.

Attachment: range_stat-0.7.patch.gz
Description: GNU Zip compressed data

Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:

Reply via email to