Switch Master and Slave role in mysql - mysql

Mysql Server1 is running as MASTER. -- server id =1
Mysql Server2 is running as SLAVE. -- server id =2
Now DB replication is happening from MASTER to SLAVE.
Switch:
Now when I stop Slave on Server2 and Configure Server1 as Slave (by command CHANGE MASTER TO MASTER_HOST=') and start Slave on server1, the replication failed with below error:
Last_IO_Errno: 1593
Last_IO_Error: Fatal error: The slave I/O thread stops because master and slave have equal MySQL server ids; these ids must be different for replication to work (or the --replicate-same-server-id option must be used on slave but this does not always make sense; please check the manual before using it).
Im using MYSQL
Pls help as im new to MYSQL.

Related

Syncing remote MySQL database with localhost from the first inserted records with MySQL Replication

I have a database myDB in the remote server (master) which has a table myTBL with some records. I want to sync the remote database with my localhost (slave) using MySQL Replication. So I have created the replication user in master and also a database with the name of myDB and the myTBL table in the localhost.
I want to use GTIDs method to syncing my databases because there is a description in MySQL website as follows:
MySQL 8.0 supports different methods of replication. The traditional
method is based on replicating events from the master's binary log,
and requires the log files and positions in them to be synchronized
between master and slave. The newer method based on global transaction
identifiers (GTIDs) is transactional and therefore does not require
working with log files or positions within these files, which greatly
simplifies many common replication tasks.
My master MySQL mysqld.cnf has:
server_id=1
enforce_gtid_consistency = on
gtid_mode = on
log_bin
log_slave_updates
and the status is:
File: ***-bin.000001
Position: 314969
Binlog_Do_DB:
Binlog_Ignore_DB:
Executed_Gtid_Set: 9a670a45-be0a-11e9-be56-52540055d8e4:1-368
and my salve mysqld.cnf has:
server-id = 2
read_only = 1
gtid_mode=ON
enforce-gtid-consistency=ON
skip-slave-start=ON
and I use the following commands to start syncing in slave:
CHANGE MASTER TO MASTER_HOST='***', MASTER_USER='***', MASTER_PASSWORD='***', MASTER_AUTO_POSITION=1;
start slave;
And every thing is OK with this status in slave:
...
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
...
So, every new record that inserted to master database is synced with my slave (localhost) database. But the records which are inserted before syncing do not placed in localhost. How can I sync them? Or in the other words, How do I start syncing from the first records? (I saw in some websites which proposed using mysqldump to dump the first data, is there a better way?)

Errno 1782 on MySQL replication

I have 3 servers configured with multi-source replication (my replication topology). It worked fine for 2 weeks, but now I getting error on a slave (server C at image):
Error executing row event: '##SESSION.GTID_NEXT cannot be set to ANONYMOUS when ##GLOBAL.GTID_MODE = ON.'
I tried to set GTID_NEXT/GTID_PURGED but it not worked.
Is possible to up this slave without reseting the master of server A (I reseted the master of server C)?
When I created the replication I setted AUTO_POSITION to 0, then if I get
the slave to run again the server C will read the missing log.
The version of MySQL is 5.7.17.
Add this line to my.cnf
slave-skip-errors = 1782

MySQL error 1236 When using GTID

I want to create a replica to my Percona Server with GTID enabled, but got this error when i show slave status:
Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: 'The slave is connecting using CHANGE MASTER TO MASTER_AUTO_POSITION = 1, but the master has purged binary logs containing GTIDs that the slave requires.'
Normally, i would stop my slave, reset it, reset master (on the slave), and get new GTID_PURGED value from the master. But this time around, the master has a very unusual value(s) and i am not sure how to determine which one to use:
mysql> show master status\G
*************************** 1. row ***************************
File: mysqld-bin.000283
Position: 316137263
Binlog_Do_DB:
Binlog_Ignore_DB:
Executed_Gtid_Set: 1570dee1-165b-11e6-a4a2-00e081e93212:1-3537,
c73f3ee7-e8d4-ee19-6507-f898a9930ccd:1-18609,
cdb70eaa-f753-ee1b-5c95-ecb8024ae729:1-2357789559:2357789561-2357790104:2357790106-2514115701:2514115703-2514115705:2514115707-2546512667
1 row in set (0.00 sec)
From the slave with the new backup copy, i get this:
root#ubuntu:/var/lib/mysql# cat xtrabackup_binlog_info
mysqld-bin.000283 294922064 1570dee1-165b-11e6-a4a2-00e081e93212:1-3537,
c73f3ee7-e8d4-ee19-6507-f898a9930ccd:1-18609,
cdb70eaa-f753-ee1b-5c95-ecb8024ae729:1-2357789559:2357789561-2357790104:2357790106-2514115701:2514115703-2514115705:2514115707-2546400960
One more thing, i just purged the binary logs on the master before i made a backup. automatic binlog purge is set to 7 days. So i know its not because the bin log has been purged as the error is suggesting.
I am running Ubuntu 14:04, and Percona server version 5.6.31-77.
How can i resolve this issue? What is the correct value of the master's GTID_PURGED?
mysql 5.6 GTID replication errors and fixes
What is GTID? 
4c2ad77f-697e-11e3-b2c3-c80aa9f17dc4
This is the server's 128 bit identification number (SERVER_UUID). It identifies where the transaction was originated. Every server has its own SERVER_UUID.
What problems GTID solves?
It is possible to identify a transaction uniquely across the replication servers. Make the automation of failover process much easier. There is no need to do calculations, inspect the binary log and so on. Just MASTER_AUTO_POSITION=1.
At application level, it is easier to do WRITE/READ split. After a write on the MASTER, you have a GTID so just check if that GTID has been executed on the SLAVE that you use for reads.
Development of new automation tools isn't a pain now.
How can I implement it?
Three variables are needed in ALL servers of the replication chain
gtid_mode: It can be ON or OFF (not 1 or 0). It enables the GTID on the server.
log_bin: Enable binary logs. Mandatory to create a replication environment.
log-slave-updates: Slave servers must log the changes that come from the master in its own binary log.
enforce-gtid-consistency: Statements that can't be logged in a transactionally safe manner are denied by the server.
ref: http://dev.mysql.com/doc/refman/5.6/en/replication-gtids-howto.html
Replication errors and fixes:
"'Got fatal error 1236 from master when reading data from binary log: "The slave is connecting using CHANGE MASTER TO MASTER_AUTO_POSITION = 1, but the master has purged binary logs containing GTIDs that the slave requires." slave_io thread stop running.
Resolution: Considering following are the master – slave UUID's
MASTER UUID: 4c2ad77f-697e-11e3-b2c3-c80aa9f17dc4
SLAVE UUID: 5b37def1-6189-11e3-bee0-e89a8f22a444
Steps:
slave>stop slave;
slave> FLUSH TABLES WITH READ LOCK;
slave>show master status;
'4c2ad77f-697e-11e3-b2c3-c80aa9f17dc4:1-83345127,5b37def1-6189-11e3-bee0-e89a8f22a444:1-13030:13032-13317:13322-13325:13328-653183:653185-654126:654128-1400817:1400820-3423394:3423401-5779965′
(HERE 83345127 Last GTID executed on master and 5779965 Last slave GTID executed on Master )
slave> reset master;
slave>set global GTID_PURGED='4c2ad77f-697e-11e3-b2c3-c80aa9f17dc4:1-83345127,5b37def1-6189-11e3-bee0-e89a8f22a444:1-5779965′;
slave>start slave;
slave>unlock tables;
slave>show slave status;
NOTE: After this Re-start slave other chain-slaves if they stop replicating;
ERROR: 'Error "Table … 'doesn"t exist" on query. Default database: …Query: "INSERT INTO OR Last_SQL_Error: ….Error 'Duplicate entry' SKIP Transaction on slave (slave_sql Thread stop running) NOTE:
SQL_SLAVE_SKIP_COUNTER doesn't work anymore with GTID.
We need to find what transaction is causing the replication to fail.
– From binary log
– From SHOW SLAVE STATUS (retrieved vs executed)
Type of errors: (check last sql error in show slave status)
Resolution: Considering following are the master – slave UUID's
MASTER UUID: 4c2ad77f-697e-11e3-b2c3-c80aa9f17dc4
SLAVE UUID: 5b37def1-6189-11e3-bee0-e89a8f22a444
slave>show slave status;
copy the 'Executed_Gtid_Set' value. '4c2ad77f-697e-11e3-b2c3-c80aa9f17dc4:1-659731804,5b37def1-6189-11e3-bee0-e89a8f22a444:1-70734947-80436012:80436021-80437839'
-Seems that slave (with uuid 5b37def1-6189-11e3-bee0-e89a8f22a444) transaction '80437840' is causing the problem here.
slave> STOP SLAVE;
slave> SET GTID_NEXT="5b37def1-6189-11e3-bee0-e89a8f22a444:80437840"; (last_executed_slave_gtid_on_master + 1)
slave> BEGIN; COMMIT;
slave> SET GTID_NEXT="AUTOMATIC";
slave> START SLAVE;
slave> show slave status;
and it's ALL SET !!!
#If using xtrabackup is the backup in the main instance.
cat xtrabackup_info | grep binlog_pos
#Use the information you gave as an example:
binlog_pos = filename 'mysqld-bin.000283', position '294922064', GTID of the last change '1570dee1-165b-11e6-a4a2-00e081e93212:1-3537,c73f3ee7-e8d4-ee19-6507-f898a9930ccd:1-18609,cdb70eaa-f753-ee1b-5c95-ecb8024ae729:1-2357789559:2357789561-2357790104:2357790106-2514115701:2514115703-2514115705:2514115707-2546400960'
#copy GTID of the last change to gtid_purged
slave>STOP SLAVE;
slave>RESET MASTER;
slave>SET GLOBAL gtid_purged='1570dee1-165b-11e6-a4a2-00e081e93212:1-3537,c73f3ee7-e8d4-ee19-6507-f898a9930ccd:1-18609,cdb70eaa-f753-ee1b-5c95-ecb8024ae729:1-2357789559:2357789561-2357790104:2357790106-2514115701:2514115703-2514115705:2514115707-2546400960';
slave>change master to master_host='master ip',master_port=master port,MASTER_USER = 'Your replicate username', MASTER_PASSWORD = 'Your replicate password',master_auto_position=1;
slave>START SLAVE;

Mysql Replication SLAVE go down

I have a problem with mysql replication.
I configure two virtual host.
Server 1 Apache + mysql Ver 15.1 Distrib 5.5.41-MariaDB
Master and SLAVE OF Server2
Server 2 mysql Ver 14.14 Distrib 5.5.42
Master and SLAVE OF Server1
Topologi MASTER + MASTER
When I restart slaves all work good, short latency and fast update. But when I wait a few minutes the replication not work more. If I update some row or make a insert or delete the slave not update the changes.
The logs not write any error, but the master_position_log is diferent between master and slave.
And if I restart the slaves all works again, the bdd is updated and the replication works well.
I don't know what happen, seems the threads sleep or death.
Thanks for some idea for fix the problem
In two cases the processes seems ok.
SERVER1
Kill 168 system user None Connect 1146 Waiting for master to send event ---
Kill 169 system user None Connect 945 Slave has read all relay log; waiting for the slave I/O thread to update it ---
Kill 170 master XXXXXXX:59273 None Binlog Dump 1145 Master has sent all binlog to slave; waiting for binlog to be updated ---
SERVER2
Kill 73 root XXXXXX:55089 None Binlog Dump 1137 Master has sent all binlog to slave; waiting for binlog to be updated ---
Kill 76 system user None Connect 1137 Waiting for master to send event ---
Kill 77 system user None Connect 985 Slave has read all relay log; waiting for the slave I/O thread to update it ---
The problem is latency.
My solution, create a CRON every minut for stop and start slave.
Now all works.
Cristian
SHOW SLAVE STATUS;
on each server. That is likely to tell you what is wrong.
You do understand the potential problems with AUTO_INCREMENT and UNIQUE keys when you are writing to both heads of a dual-Master topology?

MySQL master-slave after crash

Here's the scenario:
I have one MySQL Master and 1 slave.
master-slave replication is set and works perfectly.
The slave machine crashes.
The master machine is still up and running.
Nothing changes in the master DB.
I start the slave machine again.
I start the slave MySQL DB.
Do I need to invoke "start slave" again on the slave DB ?
10x.
I believe the slave will start automatically unless you have skip-slave-start in your my.cnf.
Run 'SHOW SLAVE STATUS' and see what it says.
In master, check the status of the master and see it shows slave is running or not.
Goto slave machine and restart(stop & start) the slave machine.
Repeat the step 1 to check again