BUG#59444

Added comments to rpl_show_relaylog_events as requested by 
reviewer.

mysql-test/extra/rpl_tests/rpl_show_relaylog_events.inc

@@ -8,6 +8,12 @@ INSERT INTO t1 VALUES (1);
 INSERT INTO t1 VALUES (2);
 INSERT INTO t1 VALUES (3);
 
+# PART I
+#
+# SHOWs contents of binary logs on the master and both, binary and
+# relay logs, on the slave.
+#
+
 --let $is_relay_log= 0
 --let $binlog_file= query_get_value(SHOW MASTER STATUS, File, 1)
 --source extra/rpl_tests/rpl_show_log_events_with_varying_options.inc
@@ -20,8 +26,21 @@ INSERT INTO t1 VALUES (3);
 --let $binlog_file= query_get_value(SHOW SLAVE STATUS, Relay_Log_File, 1)
 --source extra/rpl_tests/rpl_show_log_events_with_varying_options.inc
 
-FLUSH LOGS;
+#
+# PART II
+#
+# Although this second part of the test may seem redudant it is
+# actually needed to assert that SHOW RELAYLOG EVENTS works properly
+# with respect to the ordering of the relay log in relay-log.index. 
+#
+# If no file is specified with "IN" then first relay log file in
+# relay-log.index (ie, the oldest one) should be picked and its
+# contents displayed. The same happens for SHOW BINLOG EVENTS, so we
+# show them both. All in all, this is the reason for re-assert after
+# MASTER and SLAVE's FLUSH LOGS operations.
+#
 
+FLUSH LOGS;
 -- connection master
 FLUSH LOGS;
 DROP TABLE t1;