Fix failure to use clamp_row_est() for parallel joins.

Commit 0c2070cefa0e5d097b715c9a3b9b5499470019aa neglected to use
clamp_row_est() where it should have done so.

Patch by me.  Report by Amit Kapila.

Discussion: http://postgr.es/m/CAA4eK1KPm8RYa1Kun3ZmQj9pb723b-EFN70j47Pid1vn3ByquA@mail.gmail.com

diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index cd6dcaab190e602da4d9ae99efabbb2076cf5237..a129d1ecb3b2f94b912e3500428b782f3123c1b4 100644 (file)
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -2147,7 +2147,12 @@ final_cost_nestloop(PlannerInfo *root, NestPath *path,
 
        /* For partial paths, scale row estimate. */
        if (path->path.parallel_workers > 0)
-               path->path.rows /= get_parallel_divisor(&path->path);
+       {
+               double  parallel_divisor = get_parallel_divisor(&path->path);
+
+               path->path.rows =
+                       clamp_row_est(path->path.rows / parallel_divisor);
+       }
 
        /*
         * We could include disable_cost in the preliminary estimate, but that
@@ -2569,7 +2574,12 @@ final_cost_mergejoin(PlannerInfo *root, MergePath *path,
 
        /* For partial paths, scale row estimate. */
        if (path->jpath.path.parallel_workers > 0)
-               path->jpath.path.rows /= get_parallel_divisor(&path->jpath.path);
+       {
+               double  parallel_divisor = get_parallel_divisor(&path->jpath.path);
+
+               path->jpath.path.rows =
+                       clamp_row_est(path->jpath.path.rows / parallel_divisor);
+       }
 
        /*
         * We could include disable_cost in the preliminary estimate, but that
@@ -2952,7 +2962,12 @@ final_cost_hashjoin(PlannerInfo *root, HashPath *path,
 
        /* For partial paths, scale row estimate. */
        if (path->jpath.path.parallel_workers > 0)
-               path->jpath.path.rows /= get_parallel_divisor(&path->jpath.path);
+       {
+               double  parallel_divisor = get_parallel_divisor(&path->jpath.path);
+
+               path->jpath.path.rows =
+                       clamp_row_est(path->jpath.path.rows / parallel_divisor);
+       }
 
        /*
         * We could include disable_cost in the preliminary estimate, but that