diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index 7069f60..d2c9f51 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -86,6 +86,7 @@
 #include "optimizer/placeholder.h"
 #include "optimizer/plancat.h"
 #include "optimizer/planmain.h"
+#include "optimizer/predtest.h"
 #include "optimizer/restrictinfo.h"
 #include "parser/parsetree.h"
 #include "utils/lsyscache.h"
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c
index 9da5444..2d3c0f8 100644
--- a/src/backend/optimizer/path/indxpath.c
+++ b/src/backend/optimizer/path/indxpath.c
@@ -1798,13 +1798,13 @@ check_index_only(RelOptInfo *rel, IndexOptInfo *index)
 	 * Check that all needed attributes of the relation are available from the
 	 * index.
 	 *
-	 * XXX this is overly conservative for partial indexes, since we will
-	 * consider attributes involved in the index predicate as required even
-	 * though the predicate won't need to be checked at runtime.  (The same is
-	 * true for attributes used only in index quals, if we are certain that
-	 * the index is not lossy.)  However, it would be quite expensive to
-	 * determine that accurately at this point, so for now we take the easy
-	 * way out.
+	 * For partial indexes we won't consider attributes involved in clauses
+	 * implied by the index predicate, as those won't be needed at runtime.
+	 *
+	 * XXX The same is true for attributes used only in index quals, if we
+	 * are certain that the index is not lossy. However, it would be quite
+	 * expensive to determine that accurately at this point, so for now we
+	 * take the easy way out.
 	 */
 
 	/*
@@ -1819,6 +1819,28 @@ check_index_only(RelOptInfo *rel, IndexOptInfo *index)
 	{
 		RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
 
+		/*
+		 * If the index is partial, we won't consider the clauses that are
+		 * implied by the index predicate (those are not needed at runtime).
+		 */
+		if (index->indpred != NIL)
+		{
+			bool	implied = false;
+			List   *clauses  = NIL;
+
+			/* need a list for the 'implied_by' call */
+			clauses = lappend(clauses, (Node *) rinfo->clause);
+
+			implied = predicate_implied_by(clauses, index->indpred);
+
+			/* we generally don't free memory, but well ... */
+			list_free(clauses);
+
+			/* if the clause is implied by index predicate, skip it */
+			if (implied)
+				continue;
+		}
+
 		pull_varattnos((Node *) rinfo->clause, rel->relid, &attrs_used);
 	}
 
@@ -2138,6 +2160,15 @@ match_clause_to_index(IndexOptInfo *index,
 
 	for (indexcol = 0; indexcol < index->ncolumns; indexcol++)
 	{
+		/*
+		 * For partial indexes we skip clauses that are implied by the index
+		 * predicate. We don't need to re-evaluate those, and the columns
+		 * may not even be in the index itself, just in the predicate.
+		 */
+		if ((index->indpred != NIL) &&
+			(predicate_implied_by(list_make1(rinfo->clause), index->indpred)))
+			continue;
+
 		if (match_clause_to_indexcol(index,
 									 indexcol,
 									 rinfo))