Tech Notes:- How to verify if your connection to MySQL is using encryption or not

 It is often a confusion whether the client connection or the replication slave is using encryption while connecting to the MySQL server. The below query can tell you whether your connection is using encryption or not

SELECT sbt.variable_value AS tls_version, t2.variable_value AS cipher, processlist_user AS user, processlist_host AS host FROM performance_schema.status_by_thread  AS sbt JOIN performance_schema.threads AS t ON t.thread_id = sbt.thread_id  JOIN performance_schema.status_by_thread AS t2 ON t2.thread_id = t.thread_id  WHERE sbt.variable_name = 'Ssl_version' and t2.variable_name = 'Ssl_cipher' ORDER BY tls_version;

Of course, there are other options to find out. But this one will list all the connections which use or do not use encryption. This worked for me on MySQL 5.7. I have not tried this on other versions and for sure this does not work on some of the older versions of MySQL where we do not have performance_schema.

Tech Notes:- Got fatal error 1236 from master when reading data from binary log: 'Cannot replicate anonymous transaction when AUTO_POSITION = 1

 Last_IO_Errno: 1236
                Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: 'Cannot replicate anonymous transaction when AUTO_POSITION = 1, at file ../binlogs/mysql-bin.000006, position 194.; the first event '' at 4, the last event read from '../binlogs/mysql-bin.000006' at 259, the last byte read from '../binlogs/mysql-bin.000006' at 259.'
               Last_SQL_Errno: 1396
 Master_UUID: ab7c6739-be64-11ea-b478-080027fd2c56

Retrieved_Gtid_Set: ab7c6739-be64-11ea-b478-080027fd2c56:1-29

            Executed_Gtid_Set: 846dc749-bf34-11ea-852d-08002749f9b4:1-1032,

ab7c6739-be64-11ea-b478-080027fd2c56:1-4:30-114202

On master check the binary log 'mysql-bin.000006' at position 194

mysql> show binlog events in 'mysql-bin.000006' from 4 limit 5;
+------------------+-----+----------------+-----------+-------------+---------------------------------------------------------------------------------------------------------------+
| Log_name         | Pos | Event_type     | Server_id | End_log_pos | Info                                                                                                          |
+------------------+-----+----------------+-----------+-------------+---------------------------------------------------------------------------------------------------------------+
| mysql-bin.000006 |   4 | Format_desc    |        55 |         123 | Server ver: 5.7.30-33-log, Binlog ver: 4                                                                      |
| mysql-bin.000006 | 123 | Previous_gtids |        55 |         194 | ab7c6739-be64-11ea-b478-080027fd2c56:1-29                                                                                                    |

+------------------+-----+----------------+-----------+-------------+---------------------------------------------------------------------------------------------------------------+

The solution is to skip the transactions associated with GTID ab7c6739-be64-11ea-b478-080027fd2c56:1-29 
after making sure that this has been replicated already if not, we need to find and apply the transactions manually.

SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:1';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:2';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:3';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:4';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:5';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:6';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:7';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:8';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:9';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:10';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:11';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:12';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:13';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:14';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:15';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:16';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:17';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:18';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:19';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:20';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:21';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:22';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:23';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:24';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:25';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:26';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:27';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:28';
BEGIN;COMMIT;
SET GTID_NEXT='ab7c6739-be64-11ea-b478-080027fd2c56:29';
BEGIN;COMMIT;
SET GTID_NEXT='AUTOMATIC';

A script may be programmed to generate the above statements
Now we should be able to start the slave
start slave;

Tech Notes:- MySQL replication error 2005

The below error mostly indicates that you have a name resolution issue on your slave side. For me, it turned out that I configured the wrong IP for the DNS server. I just corrected it, stopped and started the slave and everything was ok.

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Connecting to master
                  Master_Host: master.example.com
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000004
          Read_Master_Log_Pos: 23649264
               Relay_Log_File: mysqld-relay-bin.000006
                Relay_Log_Pos: 4
        Relay_Master_Log_File: mysql-bin.000004
             Slave_IO_Running: No
            Slave_SQL_Running: Yes
              Replicate_Do_DB:
          Replicate_Ignore_DB:
           Replicate_Do_Table:
       Replicate_Ignore_Table:
      Replicate_Wild_Do_Table:
  Replicate_Wild_Ignore_Table:
                   Last_Errno: 0
                   Last_Error:
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 23649264
              Relay_Log_Space: 106
              Until_Condition: None
               Until_Log_File:
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File:
           Master_SSL_CA_Path:
              Master_SSL_Cert:
            Master_SSL_Cipher:
               Master_SSL_Key:
        Seconds_Behind_Master: NULL
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 2005
                Last_IO_Error: error connecting to master 'repl@master.example.com:3306' - retry-time: 60  retries: 86400
               Last_SQL_Errno: 0
               Last_SQL_Error:
1 row in set (0.00 sec)