复制延迟
搞明白当前的数据库在干什么
查看MySQL当前SQL的状态
利用perf top查看MySQL的调度情况
复制延迟解决方法
常规检查
所有的机器是不是一样
MySQL的版本是不是一样
相关配置是不是一样
网络是不是存在较大的延迟
IO thread延迟
master: show master status;
slave: show slave statusG read_master_log_file,read_master_log_pos < master_log_file,master_log_pos
SQL thread延迟
是否开启并行复制(主从：binlog group commit)
是否启用writeset
更改从库的事务提交配置
检查是不是存在没有主键的表
禁用表的自动收集统计信息
复制优化
master配置优化
binlog_format = row
binlog_row_image = full
gtid_mode = on
enforce_gtid_consistency = on
#binlog group commit
binlog_group_commit_sync_delay = 100
binlog_group_commit_sync_no_delay_count = 10
binlog_order_commits = off
#writeset
transaction_write_set_extraction = on
binlog_transaction_dependency_tracking = COMMIT_ORDER | WRITESET | WRITESET_SESSION
binlog_transaction_dependency_history_size = 25000
io_thread配置优化
slave_net_timeout = 20 | 30
io_thread更多的优化：change master to 相关参数
master_connect_retry = 60
master_connect_count = 24*3600
master_auto_position = 1
master_delay = 0
master_bind = ''
sql_thread配置优化
log_slave_updates
slave_parallel_type = LOGICAL_CLOCK
slave_parallel_workers = 4 | 8
slave_checkpoint_group = 512
slave_checkpoint_period = 300
slave_preserve_commit_order = on
slave_rows_search_algorithms = INDEX_SCAN,HASH_SCAN
其他优化
sync_binlog = 0
innodb_flush_log_trx_commit = 2
read_only = 1
super_read_only = 1
#binlog group commit
binlog_group_commit_sync_delay = 100
binlog_group_commit_sync_no_delay_count = 10
描述出复制原理(异步，io_thread，sql_thread，半同步)
搭建新的从库，利用复制做数据迁移
理解增强半同步复制 & binlog写入增强
binlog group commit & writeset & 并行复制
可以处理复制故障 & 理解复制延迟
理解多源复制，延迟复制，复制过滤
复制参数配置终版
binlog相关优化配置(含binlog group commit)
binlog_format = row
log_bin = /data/mysql/mysql3306/logs/mysql-bin
max_binlog_size = 1024M
binlog_rows_query_log_events = on
log_slave_updates = on
expire_logs_days = 7
binlog_cache_size = 65536 # 65535 (64k)
binlog_checksum = none # CRC32
sync_binlog = 1
slave-preserve-commit-order = on
#GTID
gtid_mode = on
enforce_gtid_consistency = on
#binlog group commit
binlog_group_commit_sync_delay = 100
binlog_group_commit_sync_no_delay_count = 10
io_thread相关优化配置
slave_net_timeout = 20 | 30 | 60
change master to ... master_connect_retry masster_retry_count master_heartbeat_period
max_relay_log_size = 8M
relay_log = relay-bin
relay_log_recovery = on
sql_thread相关优化配置(含并行复制，writeset配置)
slave_parallel_type = logical_clock
slave_parallel_workers = 4
slave_preserve_commit_order = on
slave_rows_search_algorithms = INDEX_SCAN,HASH_SCAN
#writeset
binlog_transaction_dependency_tracking = writeset | write_session
transaction_write_set_extraction = XXHASH64
半同步中参数优化配置
rpl_semi_sync_master_enabled = 1
rpl_semi_sync_slave_method = 1
rpl_semi_sync_master_timeout = 1000
其它复制相关的特性及配置
relay_log_recovery = 1
sync_relay_log_info = 1
master_info_repository = table
relay_log_info_repository = table
skip_slave_start = 1