On 14 February 2017 at 09:21, Robert Haas <robertmh...@gmail.com> wrote: > On Sun, Feb 12, 2017 at 7:16 PM, David Rowley > - table. Each worker will execute the outer side of the plan in full, which > - is why merge joins are not supported here. The outer side of a merge join > - will often involve sorting the entire inner table; even if it involves an > - index, it is unlikely to be productive to have multiple processes each > - conduct a full index scan of the inner table. > + relation. Each worker will execute the inner side of the join in full, > + which is why merge joins are not supported here. The inner side of a > merge > + join will often involve sorting the entire inner relation; even if it > + involves an index, it is unlikely to be productive to have multiple > + processes each conduct a full index scan of the inner side of the join. > > Why s/table/relation/? I don't think that's useful, especially > because the first part of that very same paragraph would still say > "table".
Perhaps it's not correct to do that. I did mean relation is the true relational theory sense, rather than where relkind = 'r'. I didn't really like the way it assumed the inner side was a table. Perhaps its better to just say "involve sorting the entire inner side of the join" -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
