On Tue, Sep 27, 2016 at 8:48 AM, Etsuro Fujita <fujita.ets...@lab.ntt.co.jp> wrote: > On 2016/09/26 20:20, Ashutosh Bapat wrote: >> >> On Mon, Sep 26, 2016 at 4:06 PM, Etsuro Fujita >> <fujita.ets...@lab.ntt.co.jp> wrote: >>> >>> On 2016/09/26 18:06, Ashutosh Bapat wrote: >>>> >>>> On Mon, Sep 26, 2016 at 1:05 PM, Etsuro Fujita >>>> <fujita.ets...@lab.ntt.co.jp> wrote: > > >>>>> ISTM that the use of the same RTI for subqueries in multi-levels in a >>>>> remote >>>>> SQL makes the SQL a bit difficult to read. How about using the >>>>> position >>>>> of >>>>> the join rel in join_rel_list, (more precisely, the position plus >>>>> list_length(root->parse->rtable)), instead? > > >>>> We switch to hash table to maintain the join RelOptInfos when the >>>> number of joins grows larger, where the position won't make much >>>> sense. > > >>> That's right, but we still store the joinrel into join_rel_list after >>> creating that hash table. > > >> As the list grows, it will take >> longer to locate the RelOptInfo of the given join. Doing that for >> creating an alias seems an overkill. > > > The join rel is appended to the end of the list, so I was thinking to get > the position info by list_length during postgresGetForeignJoinPaths.
That's true only when the paths are being added to a newly created joinrel. But that's not true always. We may add paths with different joining order to an existing joinrel, in which case list_length would not give its position. Am I missing something? -- Best Wishes, Ashutosh Bapat EnterpriseDB Corporation The Postgres Database Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
