diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c
index fd3c6b8f432..55c0fc4d73d 100644
--- a/src/backend/utils/adt/jsonfuncs.c
+++ b/src/backend/utils/adt/jsonfuncs.c
@@ -3133,18 +3133,6 @@ populate_scalar(ScalarIOData *io, Oid typid, int32 typmod, JsValue *jsv,
 
 		json = jsv->val.json.str;
 		Assert(json);
-		if (len >= 0)
-		{
-			/* Need to copy non-null-terminated string */
-			str = palloc(len + 1 * sizeof(char));
-			memcpy(str, json, len);
-			str[len] = '\0';
-		}
-		else
-		{
-			str = unconstify(char *, json);
-			len = strlen(str);
-		}
 
 		/* If converting to json/jsonb, make string into valid JSON literal */
 		if ((typid == JSONOID || typid == JSONBOID) &&
@@ -3153,12 +3141,24 @@ populate_scalar(ScalarIOData *io, Oid typid, int32 typmod, JsValue *jsv,
 			StringInfoData buf;
 
 			initStringInfo(&buf);
-			escape_json(&buf, str, len);
-			/* free temporary buffer */
-			if (str != json)
-				pfree(str);
+			if (len >= 0)
+				escape_json(&buf, json, len);
+			else
+				escape_json_cstring(&buf, json);
 			str = buf.data;
 		}
+		else if (len >= 0)
+		{
+			/* Need to copy non-null-terminated string */
+			str = palloc(len + 1 * sizeof(char));
+			memcpy(str, json, len);
+			str[len] = '\0';
+		}
+		else
+		{
+			/* string is already null-terminated */
+			str = unconstify(char *, json);
+		}
 	}
 	else
 	{