Improve wording in a few comments

Initially this was to fix the "catched" typo, but I (David) wasn't quite
clear on what the previous comment meant about being "effective".  I
expect this means efficiency, so I've reworded the comment to indicate
that.

While this is only a comment fixup, for the sake of possibly minimizing
possible future backpatching pain, I've opted to backpatch to 18 since
this code is new to that version and the release isn't out the door yet.

Author: Tender Wang <tndrwang@gmail.com>
Discussion: https://postgr.es/m/CAHewXNmSYWPud1sfBvpKbCJeRkWeZYuqatxtV9U9LvAFXBEiBw@mail.gmail.com
Backpatch-through: 18

diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c
index 601354ea3e056efe2a743a9f511295f8faecf28e..4d891aedecab077f248b7cdcf3fcec42d1188c32 100644 (file)
--- a/src/backend/optimizer/path/indxpath.c
+++ b/src/backend/optimizer/path/indxpath.c
@@ -3322,9 +3322,9 @@ match_orclause_to_indexcol(PlannerInfo *root,
        /*
         * Try to convert a list of OR-clauses to a single SAOP expression. Each
         * OR entry must be in the form: (indexkey operator constant) or (constant
-        * operator indexkey).  Operators of all the entries must match.  To be
-        * effective, give up on the first non-matching entry.  Exit is
-        * implemented as a break from the loop, which is catched afterwards.
+        * operator indexkey).  Operators of all the entries must match.  On
+        * discovery of anything unsupported, we give up by breaking out of the
+        * loop immediately and returning NULL.
         */
        foreach(lc, orclause->args)
        {
@@ -3462,9 +3462,9 @@ match_orclause_to_indexcol(PlannerInfo *root,
        }
 
        /*
-        * Catch the break from the loop above.  Normally, a foreach() loop ends
-        * up with a NULL list cell.  A non-NULL list cell indicates a break from
-        * the foreach() loop.  Free the consts list and return NULL then.
+        * Handle failed conversion from breaking out of the loop because of an
+        * unsupported qual.  Free the consts list and return NULL to indicate the
+        * conversion failed.
         */
        if (lc != NULL)
        {