> Here is the updated version, which includes the restructuring you proposed. > Other than the above issue and the alias issue we discussed, I addressed all > your comments except one on testing; I tried to add test cases where the > remote query is deparsed as nested subqueries, but I couldn't because IIUC, > reduce_outer_joins reduced full joins to inner joins or left joins.
No always. It will do so in some cases as explained in the prologue of reduce_outer_joins() * More generally, an outer join can be reduced in strength if there is a * strict qual above it in the qual tree that constrains a Var from the * nullable side of the join to be non-null. (For FULL joins this applies * to each side separately.) > So, I > added two test cases: (1) the joining relations are both base relations > (actually, we already have that) and (2) one of the joining relations is a > base relation and the other is a join relation. I rebased the patch to > HEAD, so I added a test case with aggregate pushdown also. > This patch again has a lot of unrelated changes, esp. in deparseSelectStmtForRel(). What was earlier part of deparseSelectSql() and deparseFromExpr() is now flattened in deparseSelectStmtForRel(), which seems unnecessary. Or there are changes like -deparseSelectStmtForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *rel, - List *tlist, List *remote_conds, List *pathkeys, +deparseSelectStmtForRel(StringInfo buf, PlannerInfo *root, + RelOptInfo *foreignrel, List *tlist, + List *remote_conds, List *pathkeys, which arise because rel has been renamed as foreignrel. The patch will work even without such renaming. I think such refactoring, should be done in a separate patch. -- 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
