On Fri, Aug 28, 2015 at 05:33:34PM +0900, Kyotaro HORIGUCHI wrote: > Hello, this patch enables planner to be couscious of inter-column > correlation. > > Sometimes two or more columns in a table has some correlation > which brings underestimate, which leads to wrong join method and > ends with slow execution. > > Tomas Vondra is now working on heavily-equipped multivariate > statistics for OLAP usage. In contrast, this is a lightly > implemented solution which calculates only the ratio between a > rows estimated by current method and a actual row number. I think > this doesn't conflict with his work except the grammar part.
I am very glad multi-variate statistics are being addressed. I think this is our most common cause of optimizer failures. -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + Everyone has their own god. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
