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What do I need to know about MySQL replication?
The most common task when managing a replication process is to ensure that the replication is taking place and that there have been no errors between the slave and the master. The primary statement for this is ‘ SHOW SLAVE STATUS ‘, which must be executed on each slave.
How to know replication status using a SELECT query?
You will see a variable “SLAVE_RUNNING” if it is “ON” that means replication is working fine. If it is “OFF” then replication has failed due to any reason and you need to check why? 🙂 This solution uses awk to process a show command output and sends a mail in case of errors in any of the field processed.
How is the status of a replication agent determined?
Insight on replication agent status can be collected manually or programmatically. This article will consider both cases, and also when a replication agents’ status will be determined in relation with all publications, or a particular one.
What do you need to know about MySQL 5.7?
The SHOW SLAVE STATUS statement, which you must execute on each slave, provides information about the configuration and status of the connection between the slave server and the master server. From MySQL 5.7, the Performance Schema has replication tables that provide this information in a more accessible form.
How to check the replication status of a slave?
The MASTER_HEARTBEAT_PERIOD setting on the source (set by the CHANGE MASTER TO statement) specifies the frequency of the heartbeat, which defaults to half of the connection timeout interval for the slave ( slave_net_timeout ). The Slave_last_heartbeat variable for SHOW STATUS shows when the replication slave last received a heartbeat signal.
How to check the slave status in MySQL?
The primary statement for this is SHOW SLAVE STATUS, which you must execute on each slave: The key fields from the status report to examine are: Slave_IO_State: The current status of the slave.
What does seconds behind Master mean in MySQL?
Seconds_Behind_Master: The number of seconds that the slave SQL thread is behind processing the source’s binary log. A high number (or an increasing one) can indicate that the slave is unable to handle events from the source in a timely fashion.