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Suppress unnecessary explicit sorting for EPQ mergejoin path
When building a ForeignPath for a joinrel, if there's a possibility that EvalPlanQual will be executed, we must identify a suitable path for EPQ checks. If the outer or inner path of the chosen path is a ForeignPath representing a pushed-down join, we replace it with its fdw_outerpath to ensure that the EPQ check path consists entirely of local joins. If the chosen path is a MergePath, and its outer or inner path is a ForeignPath that is not already well enough ordered, the MergePath will have non-NIL outersortkeys or innersortkeys indicating the desired ordering to be created by an explicit Sort node. If we then replace the outer or inner path with its corresponding fdw_outerpath, and that path is already sufficiently ordered, we end up in an inconsistent state: the MergePath has non-NIL outersortkeys or innersortkeys, and its input path is already properly ordered. This inconsistency can result in an Assert failure or the addition of a redundant Sort node. To fix, check if the new outer or inner path of a MergePath is already properly sorted, and set its outersortkeys or innersortkeys to NIL if so. Bug: #18902 Reported-by: Nikita Kalinin <n.kalinin@postgrespro.ru> Author: Richard Guo <guofenglinux@gmail.com> Reviewed-by: Tender Wang <tndrwang@gmail.com> Discussion: https://postgr.es/m/18902-71c1bed2b9f7c46f@postgresql.org
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Richard Guo
parent
9fef27a83b
commit
773db22269
@ -2565,6 +2565,70 @@ SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = f
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96 | 6 | 00096 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6 | 6 | foo | 96 | 6 | 00096 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6 | 6 | foo | 6 | 7 | AAA006 | 6 | 7 | AAA006 | 6 | 6 | 0006
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(10 rows)
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EXPLAIN (VERBOSE, COSTS OFF)
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SELECT * FROM ft1, ft4, ft5, local_tbl WHERE ft1.c1 = ft4.c1 AND ft1.c1 = ft5.c1
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AND ft1.c2 = local_tbl.c1 AND ft1.c1 < 100 AND ft5.c1 < 100 FOR UPDATE;
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QUERY PLAN
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----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
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LockRows
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Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft4.c1, ft4.c2, ft4.c3, ft5.c1, ft5.c2, ft5.c3, local_tbl.c1, local_tbl.c2, local_tbl.c3, ft1.*, ft4.*, ft5.*, local_tbl.ctid
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-> Merge Join
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Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft4.c1, ft4.c2, ft4.c3, ft5.c1, ft5.c2, ft5.c3, local_tbl.c1, local_tbl.c2, local_tbl.c3, ft1.*, ft4.*, ft5.*, local_tbl.ctid
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Merge Cond: (local_tbl.c1 = ft1.c2)
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-> Index Scan using local_tbl_pkey on public.local_tbl
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Output: local_tbl.c1, local_tbl.c2, local_tbl.c3, local_tbl.ctid
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-> Sort
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Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
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Sort Key: ft1.c2
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-> Foreign Scan
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Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
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Relations: ((public.ft1) INNER JOIN (public.ft4)) INNER JOIN (public.ft5)
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Remote SQL: SELECT r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, r2.c1, r2.c2, r2.c3, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2.c1, r2.c2, r2.c3) END, r3.c1, r3.c2, r3.c3, CASE WHEN (r3.*)::text IS NOT NULL THEN ROW(r3.c1, r3.c2, r3.c3) END FROM (("S 1"."T 1" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1."C 1" = r2.c1)) AND ((r1."C 1" < 100)))) INNER JOIN "S 1"."T 4" r3 ON (((r1."C 1" = r3.c1)) AND ((r3.c1 < 100)))) FOR UPDATE OF r1 FOR UPDATE OF r2 FOR UPDATE OF r3
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-> Merge Join
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Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
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Merge Cond: (ft1.c1 = ft5.c1)
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-> Merge Join
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Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft4.c1, ft4.c2, ft4.c3, ft4.*
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Merge Cond: (ft1.c1 = ft4.c1)
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-> Sort
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Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*
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Sort Key: ft1.c1
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-> Foreign Scan on public.ft1
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Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*
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Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) FOR UPDATE
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-> Sort
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Output: ft4.c1, ft4.c2, ft4.c3, ft4.*
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Sort Key: ft4.c1
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-> Foreign Scan on public.ft4
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Output: ft4.c1, ft4.c2, ft4.c3, ft4.*
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Remote SQL: SELECT c1, c2, c3 FROM "S 1"."T 3" FOR UPDATE
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-> Sort
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Output: ft5.c1, ft5.c2, ft5.c3, ft5.*
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Sort Key: ft5.c1
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-> Foreign Scan on public.ft5
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Output: ft5.c1, ft5.c2, ft5.c3, ft5.*
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Remote SQL: SELECT c1, c2, c3 FROM "S 1"."T 4" WHERE ((c1 < 100)) FOR UPDATE
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(38 rows)
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SELECT * FROM ft1, ft4, ft5, local_tbl WHERE ft1.c1 = ft4.c1 AND ft1.c1 = ft5.c1
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AND ft1.c2 = local_tbl.c1 AND ft1.c1 < 100 AND ft5.c1 < 100 FOR UPDATE;
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c1 | c2 | c3 | c4 | c5 | c6 | c7 | c8 | c1 | c2 | c3 | c1 | c2 | c3 | c1 | c2 | c3
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----+----+-------+------------------------------+--------------------------+----+------------+-----+----+----+--------+----+----+--------+----+----+------
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12 | 2 | 00012 | Tue Jan 13 00:00:00 1970 PST | Tue Jan 13 00:00:00 1970 | 2 | 2 | foo | 12 | 13 | AAA012 | 12 | 13 | AAA012 | 2 | 2 | 0002
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42 | 2 | 00042 | Thu Feb 12 00:00:00 1970 PST | Thu Feb 12 00:00:00 1970 | 2 | 2 | foo | 42 | 43 | AAA042 | 42 | 43 | AAA042 | 2 | 2 | 0002
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72 | 2 | 00072 | Sat Mar 14 00:00:00 1970 PST | Sat Mar 14 00:00:00 1970 | 2 | 2 | foo | 72 | 73 | AAA072 | 72 | 73 | | 2 | 2 | 0002
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24 | 4 | 00024 | Sun Jan 25 00:00:00 1970 PST | Sun Jan 25 00:00:00 1970 | 4 | 4 | foo | 24 | 25 | AAA024 | 24 | 25 | AAA024 | 4 | 4 | 0004
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54 | 4 | 00054 | Tue Feb 24 00:00:00 1970 PST | Tue Feb 24 00:00:00 1970 | 4 | 4 | foo | 54 | 55 | AAA054 | 54 | 55 | | 4 | 4 | 0004
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84 | 4 | 00084 | Thu Mar 26 00:00:00 1970 PST | Thu Mar 26 00:00:00 1970 | 4 | 4 | foo | 84 | 85 | AAA084 | 84 | 85 | AAA084 | 4 | 4 | 0004
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96 | 6 | 00096 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6 | 6 | foo | 96 | 97 | AAA096 | 96 | 97 | AAA096 | 6 | 6 | 0006
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36 | 6 | 00036 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6 | 6 | foo | 36 | 37 | AAA036 | 36 | 37 | | 6 | 6 | 0006
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66 | 6 | 00066 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6 | 6 | foo | 66 | 67 | AAA066 | 66 | 67 | AAA066 | 6 | 6 | 0006
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6 | 6 | 00006 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6 | 6 | foo | 6 | 7 | AAA006 | 6 | 7 | AAA006 | 6 | 6 | 0006
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48 | 8 | 00048 | Wed Feb 18 00:00:00 1970 PST | Wed Feb 18 00:00:00 1970 | 8 | 8 | foo | 48 | 49 | AAA048 | 48 | 49 | AAA048 | 8 | 8 | 0008
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18 | 8 | 00018 | Mon Jan 19 00:00:00 1970 PST | Mon Jan 19 00:00:00 1970 | 8 | 8 | foo | 18 | 19 | AAA018 | 18 | 19 | | 8 | 8 | 0008
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78 | 8 | 00078 | Fri Mar 20 00:00:00 1970 PST | Fri Mar 20 00:00:00 1970 | 8 | 8 | foo | 78 | 79 | AAA078 | 78 | 79 | AAA078 | 8 | 8 | 0008
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(13 rows)
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RESET enable_nestloop;
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RESET enable_hashjoin;
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-- test that add_paths_with_pathkeys_for_rel() arranges for the epq_path to
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@ -715,6 +715,11 @@ SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = f
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AND ft1.c2 = ft5.c1 AND ft1.c2 = local_tbl.c1 AND ft1.c1 < 100 AND ft2.c1 < 100 FOR UPDATE;
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SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = ft4.c1
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AND ft1.c2 = ft5.c1 AND ft1.c2 = local_tbl.c1 AND ft1.c1 < 100 AND ft2.c1 < 100 FOR UPDATE;
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EXPLAIN (VERBOSE, COSTS OFF)
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SELECT * FROM ft1, ft4, ft5, local_tbl WHERE ft1.c1 = ft4.c1 AND ft1.c1 = ft5.c1
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AND ft1.c2 = local_tbl.c1 AND ft1.c1 < 100 AND ft5.c1 < 100 FOR UPDATE;
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SELECT * FROM ft1, ft4, ft5, local_tbl WHERE ft1.c1 = ft4.c1 AND ft1.c1 = ft5.c1
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AND ft1.c2 = local_tbl.c1 AND ft1.c1 < 100 AND ft5.c1 < 100 FOR UPDATE;
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RESET enable_nestloop;
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RESET enable_hashjoin;
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@ -22,6 +22,7 @@
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#include "foreign/foreign.h"
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#include "funcapi.h"
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#include "miscadmin.h"
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#include "optimizer/paths.h"
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#include "tcop/tcopprot.h"
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#include "utils/builtins.h"
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#include "utils/memutils.h"
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@ -808,7 +809,23 @@ GetExistingLocalJoinPath(RelOptInfo *joinrel)
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foreign_path = (ForeignPath *) joinpath->outerjoinpath;
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if (IS_JOIN_REL(foreign_path->path.parent))
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{
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joinpath->outerjoinpath = foreign_path->fdw_outerpath;
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if (joinpath->path.pathtype == T_MergeJoin)
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{
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MergePath *merge_path = (MergePath *) joinpath;
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/*
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* If the new outer path is already well enough ordered
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* for the mergejoin, we can skip doing an explicit sort.
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*/
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if (merge_path->outersortkeys &&
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pathkeys_contained_in(merge_path->outersortkeys,
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joinpath->outerjoinpath->pathkeys))
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merge_path->outersortkeys = NIL;
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}
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}
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}
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if (IsA(joinpath->innerjoinpath, ForeignPath))
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@ -817,7 +834,23 @@ GetExistingLocalJoinPath(RelOptInfo *joinrel)
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foreign_path = (ForeignPath *) joinpath->innerjoinpath;
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if (IS_JOIN_REL(foreign_path->path.parent))
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{
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joinpath->innerjoinpath = foreign_path->fdw_outerpath;
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if (joinpath->path.pathtype == T_MergeJoin)
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{
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MergePath *merge_path = (MergePath *) joinpath;
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/*
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* If the new inner path is already well enough ordered
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* for the mergejoin, we can skip doing an explicit sort.
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*/
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if (merge_path->innersortkeys &&
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pathkeys_contained_in(merge_path->innersortkeys,
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joinpath->innerjoinpath->pathkeys))
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merge_path->innersortkeys = NIL;
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}
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}
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}
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return (Path *) joinpath;
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