How is a GTID built in MySQL replication?
GTID is built from two parts – the unique identifier of a server where a transaction was first executed, and a sequence number. In the above example, we can see that the transaction was executed by the server with server_uuid of ‘966073f3-b6a4-11e4-af2c-080027880ca6’ and it’s 4th transaction executed there.
How is MySQL Replication based on binary events?
For years, MySQL replication used to be based on binary log events – all a slave knew was the exact event and the exact position it just read from the master. Any single transaction from a master may have ended in different binary logs, and in different positions in these logs.
Why do I need to stop replication in MySQL?
Any single transaction from a master may have ended in different binary logs, and in different positions in these logs. It was a simple solution that came with limitations – more complex topology changes could require an admin to stop replication on the hosts involved.
What happens when a slave misses a GTID transaction?
One of the most important things to keep in mind regarding GTID is that a slave, when connecting to the master, checks if it is missing any transactions which were executed on the master. These are called errant transactions. If a slave finds such transactions, it will execute them. Let’s assume we ran following SQL to clear an offending row: ?
How to fix MySQL replication after an incompatible DDL command?
You can simply promote the slave to get the old performance back. The MySQL manual says that ROW based replication can be used to replicate to a lower version, provided that no DDLs replicated are incompatible with the slave. One such incompatible command is ALTER USER which is a new feature in MySQL 5.7 and not available on 5.6. :
When to start a replica in MySQL 8.0?
The START REPLICA | SLAVE clauses UNTIL SQL_BEFORE_GTIDS and UNTIL SQL_AFTER_GTIDS can be used to make a replica process transactions only up to the first GTID in a GTID set, or stop after the last GTID in a GTID set. The built-in functions GTID_SUBSET () and GTID_SUBTRACT () require GTID sets as input.
How does statement based replication work in MySQL?
Statement-based replication will replicate the exact queries used in the batch jobs, so if the query took half an hour to process on the master, the slave thread will be stalled for at least the same amount of time. This means no other data can replicate and the slave nodes will start lagging behind the master.