On Tue, Oct 10, 2017 at 07:29:24PM +0530, Gourav Kumar wrote: > When you fire a query in postgresql, it will first parse the query and > create the data structures for storing various aspects of the query and > executing the query. (Like RangeTblEntry, PlannerInfo, RangeOptInfo etc.). > > I want to know how does postgresql stores the join predicates of a query. > Like which data structure is used to store the join predicates. > > How can we find the join predicates applied on a relation from relid, Oid > or RangeTblEntry ? > > I want to construct a join graph for a given query, for which I need the > join predicates between two relations.
In the usingClause or quals fields of a JoinExpr. See src/backend/parser/gram.y, search for join_qual. Of course, WHERE clauses have to be inspected as well, which go into the whereClause of of a SelectStmt; search for where_clause in src/backend/parser/gram.y. Nico -- -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
