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What is Semisynchronous replication?
Semisynchronous replication falls between asynchronous and fully synchronous replication. The source waits until at least one replica has received and logged the events (the required number of replicas is configurable), and then commits the transaction.
Is MySQL trigger asynchronous?
Yes, triggers are synchronous. However if you need to implement asynchronous MySQL triggers you can utilize Maxwell + custom code to easily read MySQL binary log and launch your own logic on interesting events.
How does MySQL 5.7 support semisynchronous replication?
In addition to the built-in asynchronous replication, MySQL 5.7 supports an interface to semisynchronous replication that is implemented by plugins. This section discusses what semisynchronous replication is and how it works.
Why is semisynchronous replication best for close servers?
The amount of slowdown is at least the TCP/IP roundtrip time to send the commit to the replica and wait for the acknowledgment of receipt by the replica. This means that semisynchronous replication works best for close servers communicating over fast networks, and worst for distant servers communicating over slow networks.
Why does MySQL failover from source to replica?
With asynchronous replication, if the source crashes, transactions that it has committed might not have been transmitted to any replica. Failover from source to replica in this case might result in failover to a server that is missing transactions relative to the source.
What is the RPL _ semi Sync Master wait point variable?
The rpl_semi_sync_master_wait_point system variable controls the point at which a semisynchronous replication source waits for replica acknowledgment of transaction receipt before returning a status to the client that committed the transaction. These values are permitted: