Hey ambud, Thank you for your inputs. That part we are 100% confident. Because when the stats are missing for any of the column featuring in the query, the CBO will log "stats not available for field. skipping CBO." so we made sure we covered all the fields.
On Tue, Feb 12, 2019 at 11:58 AM Ambud Sharma <ambudsha...@pinterest.com> wrote: > As long as column stats are available for all tables, Hive CBO will try to > do the optimization when generating query plan. > > On Tue, Feb 12, 2019, 11:48 AM Venkatesh Selvaraj < > venkateshselva...@pinterest.com wrote: > >> Hello All, >> >> I would like to know if anyone of you faced this issue with HIVE CBO and >> also would like to get some directions as to how to go about resolving it. >> >> We are using Hive 1.2.1. When we were evaluating the benefits of Cost >> based Optimization(CBO), we stumbled upon this. >> >> 1) Queries which had single level join when run always had this thing in >> the log. "Not invoking CBO because the statement has too few joins". >> Can anyone confirm this. Join optimization happens only when there are more >> than 1 join? Is there a way around this. >> >> 2) Also, Can CBO automatically do a Map join(without Hive's set >> auto-convert statement) if assesses that one of the table involved is small >> and could be broadcasted? >> >> Thanks in advance!! >> >> Regards, >> Venkatesh Selvaraj >> > -- Regards, Venkatesh Selvaraj
