On Fri, Nov 27, 2015 at 1:25 AM, Kouhei Kaigai <kai...@ak.jp.nec.com> wrote: >> Sorry, I don't understand this. In my understanding, fdw_recheck_quals >> can be defined for a foreign join, regardless of the join type, >> > Yes, "can be defined", but will not be workable if either side of > joined tuple is NULL because of outer join. SQL functions returns > NULL prior to evaluation, then ExecQual() treats this result as FALSE. > However, a joined tuple that has NULL fields may be a valid tuple. > > We don't need to care about unmatched tuple if INNER JOIN.
This is a really good point, and a very strong argument for the design KaiGai has chosen here. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
