mysql operation and maintenance diary

MySQL semi-synchronous replication
　　Semi-synchronous features
　　　　Receiving ack or closing the semi-synchronization overtime
　　　　The slave library only sends an ack to the waiting thread of the master library after flushing the binlog to the repay log. After the
　　　　timeout is converted to asynchronous replication, when at least one semi-synchronous slave node catches up Up is, the main library will be automatically converted to semi-synchronous replication
　　　　Semi-synchronous must be open on both the master and slave libraries, otherwise it will be asynchronous replication

　　　　. Semi-synchronized with the time used for receiving (multiple IDC deployments have at least one slave locally) after_flush on
　　the main library side
　　　　-- only the last event needs to send ACK
　　　　after_sync -- the data from the slave library may exceed the data from the master library
　　　　after_commit -- the slave library will lose data , the main library waits
　　　　after_rollback after commit -- same as after_commit
　　　　transmit_start -- make judgment before sending binlog, all main library threads waiting for this point can not wait, directly commit
　　　　transmit_stop -- the main library wants to send binlog from the library to end Afterward_send_event
　　　　-- before sending binlog, do you need to send ACK information from the library
　　　　after_send_event -- after the binlog is sent,
　　　　after_reset_master -- after the reset_master statement is executed
　　Semi-synchronous slave side
　　Semi-synchronous implementation
　　Plug-in installation
　　Semi-synchronous automatic switch

MySQL5.7 multi-threaded replication
　　Delay optimization method
　　　　Increase buffer_pool size, cache more data, reduce IO pressure
　　　　Increase log_buffer_size and group, reduce buffer_pool brush IO, improve write performance
　　　　Modify flush_method For O_DIRECT, improve write performance
　　　　If possible, turn off binlog from the library, or log_slave_uodates and
　　　　modify the parameter innodb_flush_log_at_trx_commit to 0 or 2.
　　　　If binlog is not turned off, modify the parameter sync_binlog to 0 or a larger number to reduce IO pressure
　　MySQL5.6 Multi-threaded replication
　　　　1. There are more databases
　　　　2. The writing of each database is relatively uniform
　　　　Because the MySQL 5.6 replication distribution level is set to the library
　　MySQL 5.7 multi-threaded replication
　　　　All transactions in the prepare phase can submit
　　　　　　last_commit
　　　　ordered commit in parallel