Add key info to the hash join plan output

Author: dyemanov

src/jrd/recsrc/HashJoin.cpp

@@ -481,7 +481,11 @@ void HashJoin::internalGetPlan(thread_db* tdbb, PlanEntry& planEntry, unsigned l
 {
 	planEntry.className = "HashJoin";
 
-	planEntry.lines.add().text = "Hash Join (inner)";
+	string extras;
+	extras.printf(" (keys: %" ULONGFORMAT", total key length: %" ULONGFORMAT")",
+				  m_leader.keys->getCount(), m_leader.totalKeyLength);
+
+	planEntry.lines.add().text = "Hash Join (inner)" + extras;
 	printOptInfo(planEntry.lines);
 
 	if (recurse)