diff options
Diffstat (limited to 'src/backend/foreign/foreign.c')
| -rw-r--r-- | src/backend/foreign/foreign.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c index f0835fc3070..9c57f7a259c 100644 --- a/src/backend/foreign/foreign.c +++ b/src/backend/foreign/foreign.c @@ -22,6 +22,7 @@ #include "foreign/foreign.h" #include "funcapi.h" #include "miscadmin.h" +#include "optimizer/paths.h" #include "tcop/tcopprot.h" #include "utils/builtins.h" #include "utils/memutils.h" @@ -808,7 +809,23 @@ GetExistingLocalJoinPath(RelOptInfo *joinrel) foreign_path = (ForeignPath *) joinpath->outerjoinpath; if (IS_JOIN_REL(foreign_path->path.parent)) + { joinpath->outerjoinpath = foreign_path->fdw_outerpath; + + if (joinpath->path.pathtype == T_MergeJoin) + { + MergePath *merge_path = (MergePath *) joinpath; + + /* + * If the new outer path is already well enough ordered + * for the mergejoin, we can skip doing an explicit sort. + */ + if (merge_path->outersortkeys && + pathkeys_contained_in(merge_path->outersortkeys, + joinpath->outerjoinpath->pathkeys)) + merge_path->outersortkeys = NIL; + } + } } if (IsA(joinpath->innerjoinpath, ForeignPath)) @@ -817,7 +834,23 @@ GetExistingLocalJoinPath(RelOptInfo *joinrel) foreign_path = (ForeignPath *) joinpath->innerjoinpath; if (IS_JOIN_REL(foreign_path->path.parent)) + { joinpath->innerjoinpath = foreign_path->fdw_outerpath; + + if (joinpath->path.pathtype == T_MergeJoin) + { + MergePath *merge_path = (MergePath *) joinpath; + + /* + * If the new inner path is already well enough ordered + * for the mergejoin, we can skip doing an explicit sort. + */ + if (merge_path->innersortkeys && + pathkeys_contained_in(merge_path->innersortkeys, + joinpath->innerjoinpath->pathkeys)) + merge_path->innersortkeys = NIL; + } + } } return (Path *) joinpath; |