Update comment in set_dummy_rel_pathlist().

This comment claimed that set_dummy_rel_pathlist() has callers
other than (possibly indirectly) set_rel_size().  It doesn't,
so revise the argument to not rely on that.

Noted by Richard Guo.

Discussion: https://postgr.es/m/CAMbWs4-KFEU_fDuJPNCOkUu3rwvZvKBEytkd9VrM4kH4-2h1CQ@mail.gmail.com

diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 7bad4044580ee7889fbe60697c5902ad590ffd97..3151ad1f64be7a6bbe16dd3f0d45f38e6fd9625b 100644 (file)
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -2180,9 +2180,9 @@ set_dummy_rel_pathlist(RelOptInfo *rel)
 
        /*
         * We set the cheapest-path fields immediately, just in case they were
-        * pointing at some discarded path.  This is redundant when we're called
-        * from set_rel_size(), but not when called from elsewhere, and doing it
-        * twice is harmless anyway.
+        * pointing at some discarded path.  This is redundant in current usage
+        * because set_rel_pathlist will do it later, but it's cheap so we keep it
+        * for safety and consistency with mark_dummy_rel.
         */
        set_cheapest(rel);
 }