I just tried to execute "set global log_queries_not_using_indexes=ON;" on master, but slave not sync the same system variables.
So i'm confused that what does mysql master sync to slave by binlog?
include information_schema?
Related
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?)
I had MySQL master slave replication configured. I accidently ran Reset Slave on slave instance. I do not have a note of the last bin log position of the master that the slave had completed. Show slave status command returns a blank row as I have reset the slave.
Is there any way in which I can recover the last bin log position that the Slave had finished syncing? Or is there any other way in which I can fix the replication without setting it up fresh?
I'm a beginner for MySQL Master-Slave .
and I have read two tutorials .
How to Setup MariaDB (Master-Slave) Replication
Setup MariaDB Master-Slave Replication
In first tutorial. It make me that
[mysqld] Master section
log-bin
server_id=1
replicate-do-db=employees
bind-address=192.168.0.18
[mysqld] SLAVE Section
server_id=2
replicate-do-db=employees
But in the second tutorial, it show me that
[mysqld] Master
server_id=1
log-basename=master
log-bin
binlog-format=row
binlog-do-db=unixmen
[mysqld] Slave
server-id = 2
replicate-do-db=unixmen
And why I should LOCK TABLES, and mysqldump sql, then import it ?
FLUSH TABLES WITH READ LOCK;
DISCLAIMER: To keep things easy and non-confusing here, I talk about a simple 1 Master - 1 Slave setup. No chains, no master-master, or whatever...
Your first tutorial is wrong, it should be binlog-do-db there.
Replication works like this.
The master writes all transactions into its binary log.
The slave reads the transactions from masters binary log and writes them to its relay log.
Only after that the slave executes the statements from its relay log.
binlog-do-db makes the master write only statements for the specified DB into its binary log.
replicate-do-db makes the slave just read statements from the relay log, that are for the specified DB.
replicate-do-db has no effect on the master, since there is no relay log to read from.
The LOCK TABLES part is there, so that the data is consistent. It prevents that the data on the master is modified while backing up the data is still in process.
You restore the database from this backup on the slave, because when you set up a slave, you don't always start from fresh. Therefore it's made so, that you just provide the same data basis on both servers, then you tell the slave at which transaction coordinates the master is and voila, you can start your replication. You can also unlock the master after having dumped the data. Just make sure, that you get the slave up in time before statements in the binary log get lost due to log rotation.
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
Quick questions about MySQL Master-Slave-Slave set-ups:
I currently have a Master-Slave set up right now and I would like to add another slave. Would it be possible to clone the server running the slave, and then spin up a new server with the image from the slave, and have it pick up right where it left off? So whatever the binlog was at the time of the copy it would just run until it catches up with the master?
Ideally - I'm trying to start another slave the connects to the master without shutting down the Master for a backup. Any advice or guidance would be great. Thanks!
Yes, you can shutdown slave instance, and copy all it's data to another slave (including logs).
Don't forget to edit my.cnf on second slave (you should change server-id)
Then start both slave servers
Yes this is possible. The best way would probably be to temporarily pause the replication on the slave, determine the master binary log position information, then make your dump from the replica while replication is still paused (and no other data is changing on the replica). After the dump is complete you can restart the replica.
On the new server, just install the dump, set the binlog coordinates and start up the replication. A word of caution though. Make sure your settings for purging the binary logs on the master will allow for retention of the binary logs for long enough for you to do this set up process and get the new slave caught up before the bin logs are purged.
Here's a good tutorial on how to setup multiple replication slaves for a master server:
http://arcib.dowling.edu/cgi-bin/info2html?%28mysql%29replication-howto
It doesn't explain your scenario, but gives important hints: you must assign a unique server-id to your second slave.
Regarding your problem: If your masters binary log is kept long enough, you should not get into trouble. Just shutdown your slave for a moment, clone it and write down: MASTER_LOG_FILE and MASTER_LOG_POS of the slave; then restart the original slave and setup the second slave correctly: that means with that given MASTER_LOG_POS and *_FILE set and a unique server-id in my.cnf;
Then start up your second slave. Use "START SLAVE" to start the replication and then have a look at "SHOW SLAVE STATUS;"
Regards,
Stefan
PS: Cannot promise this to work, but I'm quit sure it should do.
You can use existing mysql slave to make a new one just do the following steps,
Stop replication on slave.
execute show slave status; and note these values Master_Log_File: master-bin.000002 &
Read_Master_Log_Pos: 1307
Take mysqldump and restore it on new mysql slave server, you can copy my.cnf file from existing mysql slave server and just change server-id.
execute change master to command on new slave server providing details of mysql master server and log file name and log position which we obtained from existing mysql slave.
execute start slave; on existing mysql slave.
to verify slave status run show slave status.
that's it you have a new mysql slave server!!
Good luck !