之前已經詳細介紹了Mysql基於GTID主從複製的概念,原理和配置,下面整體記錄下MySQL5.7基於GTID主從複製+並行複製+增強半同步複製+讀寫分離環境的實現過程,以便加深對mysql新特性GTID複製的理解和實際業務場景中部署應用。
一、實驗環境
[root@mysql-master ~]# cat /etc/redhat-release CentOS Linux release 7.5.1804 (Core) 為了方便實驗,關閉所有節點的防火牆 [root@mysql-master ~]# systemctl stop firewalld [root@mysql-master ~]# firewall-cmd --state not running [root@mysql-master ~]# cat /etc/sysconfig/selinux |grep "SELINUX=disabled" SELINUX=disabled [root@mysql-master ~]# setenforce 0 setenforce: SELinux is disabled [root@mysql-master ~]# getenforce Disabled
二、安裝Mysql5.7
在三個mysql節點機上使用yum方式安裝Mysql5.7,參考:https://www.cnblogs.com/kevingrace/p/8340690.html 安裝MySQL yum資源庫 [root@mysql-master ~]# yum localinstall https://dev.mysql.com/get/mysql57-community-release-el7-8.noarch.rpm 安裝MySQL 5.7 [root@mysql-master ~]# yum install -y mysql-community-server 啟動MySQL伺服器和MySQL的自動啟動 [root@mysql-master ~]# systemctl start mysqld.service [root@mysql-master ~]# systemctl enable mysqld.service 設定登入密碼 由於MySQL從5.7開始不允許首次安裝後使用空密碼進行登入!為了加強安全性,系統會隨機生成一個密碼以供管理員首次登入使用, 這個密碼記錄在/var/log/mysqld.log檔案中,使用下面的命令可以檢視此密碼: [root@mysql-master ~]# cat /var/log/mysqld.log|grep 'A temporary password' 2019-01-11T05:53:17.824073Z 1 [Note] A temporary password is generated for root@localhost: TaN.k:*Qw2xs 使用上面檢視的密碼TaN.k:*Qw2xs 登入mysql,並重置密碼為123456 [root@mysql-master ~]# mysql -p #輸入預設的密碼:TaN.k:*Qw2xs ............. mysql> set global validate_password_policy=0; Query OK, 0 rows affected (0.00 sec) mysql> set global validate_password_length=1; Query OK, 0 rows affected (0.00 sec) mysql> set password=password("123456"); Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> flush privileges; Query OK, 0 rows affected (0.00 sec) 檢視mysql版本 [root@mysql-master ~]# mysql -p123456 ........ mysql> select version(); +-----------+ | version() | +-----------+ | 5.7.24 | +-----------+ 1 row in set (0.00 sec) ===================================================================== 溫馨提示 mysql5.7通過上面預設安裝後,執行語句可能會報錯: ERROR 1819 (HY000): Your password does not satisfy the current policy requirements 這個報錯與Mysql 密碼安全策略validate_password_policy的值有關,validate_password_policy可以取0、1、2三個值: 解決辦法: set global validate_password_policy=0; set global validate_password_length=1;
三、配置基於GTID的主從複製
傳統的基於binlog position複製的方式有個嚴重的缺點:如果slave連線master時指定的binlog檔案錯誤或者position錯誤,會造成遺漏或者重複,
很多時候前後資料是有依賴性的,這樣就會出錯而導致資料不一致。
從MYSQL5.6開始,mysql開始支援GTID複製。GTID的全稱是global transaction id,表示的是全域性事務ID。GTID的分配方式為uuid:trans_id,其中:uuid是每個mysql伺服器都唯一的,記錄在$datadir/auto.cnf中。如果複製結構中,任意兩臺伺服器uuid重複的話(比如直接冷備份時,auto.conf中的內容是一致的),在啟動複製功能的時候會報錯。這時可以刪除auto.conf檔案再重啟mysqld。
基於GTID主從複製的優點大致有:
- 保證同一個事務在某slave上絕對只執行一次,沒有執行過的gtid事務總是會被執行。
- 不用像傳統複製那樣保證binlog的座標準確,因為根本不需要binlog以及座標。
- 故障轉移到新的master的時候很方便,簡化了很多工。
- 很容易判斷master和slave的資料是否一致。只要master上提交的事務在slave上也提交了,那麼一定是一致的。
- 當然,MySQL提供了選項可以控制跳過某些gtid事務,防止slave第一次啟動複製時執行master上的所有事務而導致耗時過久。
- 雖然對於row-based和statement-based的格式都能進行gtid複製,但建議採用row-based格式。
基於GTID主從複製環境部署記錄
1)mysql-master主資料庫上的操作 在my.cnf檔案中配置GTID主從複製 [root@mysql-master ~]# cp /etc/my.cnf /etc/my.cnf.bak [root@mysql-master ~]# >/etc/my.cnf [root@mysql-master ~]# cat /etc/my.cnf [mysqld] datadir = /var/lib/mysql socket = /var/lib/mysql/mysql.sock symbolic-links = 0 log-error = /var/log/mysqld.log pid-file = /var/run/mysqld/mysqld.pid #GTID: server_id = 1 gtid_mode = on enforce_gtid_consistency = on #binlog log_bin = mysql-bin log-slave-updates = 1 binlog_format = row sync-master-info = 1 sync_binlog = 1 #relay log skip_slave_start = 1 配置後,記得重啟mysql服務 [root@mysql-master ~]# systemctl restart mysqld 登入mysql,並檢視master狀態, 發現多了一項"Executed_Gtid_Set " mysql> show master status; +-------------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-------------------+----------+--------------+------------------+-------------------+ | mysql-bin.000001 | 154 | | | | +-------------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec) mysql> show global variables like '%uuid%'; +---------------+--------------------------------------+ | Variable_name | Value | +---------------+--------------------------------------+ | server_uuid | 317e2aad-1565-11e9-9c2e-005056ac6820 | +---------------+--------------------------------------+ 1 row in set (0.00 sec) 檢視確認gtid功能開啟 mysql> show global variables like '%gtid%'; +----------------------------------+-------+ | Variable_name | Value | +----------------------------------+-------+ | binlog_gtid_simple_recovery | ON | | enforce_gtid_consistency | ON | | gtid_executed | | | gtid_executed_compression_period | 1000 | | gtid_mode | ON | | gtid_owned | | | gtid_purged | | | session_track_gtids | OFF | +----------------------------------+-------+ 8 rows in set (0.00 sec) 檢視確認binlog日誌功能開啟 mysql> show variables like 'log_bin'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | log_bin | ON | +---------------+-------+ 1 row in set (0.00 sec) 授權slave複製使用者,並重新整理許可權 mysql> grant replication slave,replication client on *.* to slave@'172.16.60.212' identified by "slave@123"; Query OK, 0 rows affected, 1 warning (0.03 sec) mysql> flush privileges; Query OK, 0 rows affected (0.04 sec) mysql> show grants for slave@'172.16.60.212'; +-------------------------------------------------------------------------------+ | Grants for slave@172.16.60.212 | +-------------------------------------------------------------------------------+ | GRANT REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'slave'@'172.16.60.212' | +-------------------------------------------------------------------------------+ 1 row in set (0.00 sec) 再次檢視master狀態 mysql> show master status; +-------------------+----------+--------------+------------------+------------------------------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-------------------+----------+--------------+------------------+------------------------------------------+ | mysql-bin.000001 | 622 | | | 317e2aad-1565-11e9-9c2e-005056ac6820:1-2 | +-------------------+----------+--------------+------------------+------------------------------------------+ 1 row in set (0.00 sec) 這裡需要注意一下: 啟動配置之前,同樣需要對從伺服器進行初始化。對從伺服器初始化的方法基本和基於日誌點是相同的,只不過在啟動了GTID模式後, 在備份中所記錄的就不是備份時的二進位制日誌檔名和偏移量了,而是記錄的是備份時最後的GTID值。 需要先在主資料庫機器上把目標庫備份一下,假設這裡目標庫是kevin(為了測試效果,下面手動建立) mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | +--------------------+ 4 rows in set (0.00 sec) mysql> CREATE DATABASE kevin CHARACTER SET utf8 COLLATE utf8_general_ci; Query OK, 1 row affected (0.02 sec) mysql> use kevin; Database changed mysql> create table if not exists haha (id int(10) PRIMARY KEY AUTO_INCREMENT,name varchar(50) NOT NULL); Query OK, 0 rows affected (0.27 sec) mysql> insert into kevin.haha values(1,"congcong"),(2,"huihui"),(3,"grace"); Query OK, 3 rows affected (0.06 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> select * from kevin.haha; +----+----------+ | id | name | +----+----------+ | 1 | congcong | | 2 | huihui | | 3 | grace | +----+----------+ 3 rows in set (0.00 sec) 把kevin庫備份出來 [root@mysql-master ~]# mysqldump --single-transaction --master-data=2 --triggers --routines --databases kevin -uroot -p123456 > /root/kevin.sql 這裡稍微注意下: mysql5.6使用mysqldump備份時,指定備份的具體庫,使用--database mysql5.7使用mysqldump備份時,指定備份的具體庫,使用--databases [root@mysql-master ~]# ls /root/kevin.sql /root/kevin.sql [root@mysql-master ~]# cat /root/kevin.sql -- MySQL dump 10.13 Distrib 5.7.24, for Linux (x86_64) -- -- Host: localhost Database: kevin -- ------------------------------------------------------ -- Server version 5.7.24-log ............. ............. -- -- GTID state at the beginning of the backup -- SET @@GLOBAL.GTID_PURGED='317e2aad-1565-11e9-9c2e-005056ac6820:1-5'; 然後把備份的/root/kevin.sql檔案拷貝到mysql-slave1從資料庫伺服器上 [root@mysql-master ~]# rsync -e "ssh -p22" -avpgolr /root/kevin.sql root@172.16.60.212:/root/ ============================================================== 2)mysql-slave1從資料庫上的操作 在my.cnf檔案中配置GTID主從複製 與主伺服器配置大概一致,除了server_id不一致外,從伺服器還可以在配置檔案裡面新增:"read_only=on" , 使從伺服器只能進行讀取操作,此引數對超級使用者無效,並且不會影響從伺服器的複製; [root@mysql-slave1 ~]# cp /etc/my.cnf /etc/my.cnf.bak [root@mysql-slave1 ~]# >/etc/my.cnf [root@mysql-slave1 ~]# vim /etc/my.cnf [mysqld] datadir = /var/lib/mysql socket = /var/lib/mysql/mysql.sock symbolic-links = 0 log-error = /var/log/mysqld.log pid-file = /var/run/mysqld/mysqld.pid #GTID: server_id = 2 gtid_mode = on enforce_gtid_consistency = on #binlog log_bin = mysql-bin log-slave-updates = 1 binlog_format = row sync-master-info = 1 sync_binlog = 1 #relay log skip_slave_start = 1 read_only = on 配置完成後,記得重啟mysql服務 [root@mysql-slave1 ~]# systemctl restart mysqld 接著將主資料庫目標庫的備份資料kevin.sql匯入到從資料庫裡 [root@mysql-slave1 ~]# ls /root/kevin.sql /root/kevin.sql [root@mysql-slave1 ~]# mysql -p123456 ......... mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | +--------------------+ 4 rows in set (0.00 sec) mysql> source /root/kevin.sql; mysql> select * from kevin.haha; +----+----------+ | id | name | +----+----------+ | 1 | congcong | | 2 | huihui | | 3 | grace | +----+----------+ 3 rows in set (0.00 sec) 在從資料庫裡,使用change master 配置主從複製 mysql> stop slave; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> change master to master_host='172.16.60.211',master_user='slave',master_password='slave@123',master_auto_position=1; Query OK, 0 rows affected, 2 warnings (0.26 sec) mysql> start slave; Query OK, 0 rows affected (0.02 sec) mysql> show slave status \G; *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 172.16.60.211 Master_User: slave Master_Port: 3306 Connect_Retry: 60 Master_Log_File: mysql-bin.000001 Read_Master_Log_Pos: 1357 Relay_Log_File: mysql-slave1-relay-bin.000002 Relay_Log_Pos: 417 Relay_Master_Log_File: mysql-bin.000001 Slave_IO_Running: Yes Slave_SQL_Running: Yes ................ ................ Executed_Gtid_Set: 317e2aad-1565-11e9-9c2e-005056ac6820:1-5 Auto_Position: 1 由上面可知,mysql-slave1節點已經和mysql-master節點配置了主從同步關係 3) mysql-master主資料庫上進行狀態檢視和測試測試插入 mysql> show master status; +-------------------+----------+--------------+------------------+------------------------------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-------------------+----------+--------------+------------------+------------------------------------------+ | mysql-bin.000001 | 1357 | | | 317e2aad-1565-11e9-9c2e-005056ac6820:1-5 | +-------------------+----------+--------------+------------------+------------------------------------------+ 1 row in set (0.00 sec) mysql> show slave hosts; +-----------+------+------+-----------+--------------------------------------+ | Server_id | Host | Port | Master_id | Slave_UUID | +-----------+------+------+-----------+--------------------------------------+ | 2 | | 3306 | 1 | 2c1efc46-1565-11e9-ab8e-00505688047c | +-----------+------+------+-----------+--------------------------------------+ 1 row in set (0.00 sec) mysql> insert into kevin.haha values(4,"beijing"),(5,"hefei"),(10,"xihu"); Query OK, 3 rows affected (0.06 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> delete from kevin.haha where id<4; Query OK, 3 rows affected (0.10 sec) mysql> select * from kevin.haha; +----+---------+ | id | name | +----+---------+ | 4 | beijing | | 5 | hefei | | 10 | xihu | +----+---------+ 3 rows in set (0.00 sec) 4)mysql-slave1從資料庫上檢視 mysql> select * from kevin.haha; +----+---------+ | id | name | +----+---------+ | 4 | beijing | | 5 | hefei | | 10 | xihu | +----+---------+ 3 rows in set (0.00 sec) 發現mysql-slave1從資料庫已經將新插入的資料同步過來了,由此,基於GTID的主從同步複製關係已經正常部署完成了!
四、並行複製 (解決主從複製延遲問題)
一般Mysql主從複製有三個執行緒參與,都是單執行緒:Binlog Dump(主) -> IO Thread (從) -> SQL Thread(從)。複製出現延遲一般出在兩個地方:
- SQL執行緒忙不過來 (可能需要應用資料量較大,可能和從庫本身的一些操作有鎖和資源的衝突;主庫可以併發寫,SQL執行緒不可以;主要原因)
- 網路抖動導致IO執行緒複製延遲(次要原因)。
MySQL主從複製延遲的解決辦法:MySQL從5.6開始有了SQL Thread多個的概念,可以併發還原資料,即並行複製技術。並行複製的機制,是MySQL的一個非常重要的特性,可以很好的解決MySQL主從延遲問題!
在MySQL 5.6中,設定引數slave_parallel_workers = 4(>1),即可有4個SQL Thread(coordinator執行緒)來進行並行複製,其狀態為:Waiting for an evant from Coordinator。但是其並行只是基於Schema的,也就是基於庫的。如果資料庫例項中存在多個Schema,這樣設定對於Slave複製的速度可以有比較大的提升。通常情況下單庫多表是更常見的一種情形,那基於庫的併發就沒有卵用。其核心思想是:不同schema下的表併發提交時的資料不會相互影響,即slave節點可以用對relay log中不同的schema各分配一個類似SQL功能的執行緒,來重放relay log中主庫已經提交的事務,保持資料與主庫一致。
MySQL 5.6版本支援所謂的並行複製,但是其並行只是基於schema的,也就是基於庫的。如果使用者的MySQL資料庫例項中存在多個schema,對於從機複製的速度的確可以有比較大的幫助。但是基於schema的並行複製存在兩個問題:
1) crash safe功能不好做,因為可能之後執行的事務由於並行複製的關係先完成執行,那麼當發生crash的時候,這部分的處理邏輯是比較複雜的。
2) 最為關鍵的問題是這樣設計的並行複製效果並不高,如果使用者例項僅有一個庫,那麼就無法實現並行回放,甚至效能會比原來的單執行緒更差。而 單庫多表是比多庫多表更為常見的一種情形 。
注意:mysql 5.6的MTS是基於庫級別的並行,當有多個資料庫時,可以將slave_parallel_workers設定為資料庫的數量,為了避免新建庫後來回修改,也可以將該引數設定的大一些。設定為庫級別的事務時,不允許這樣做,會報錯。
在MySQL 5.7中,引入了基於組提交的並行複製(官方稱為Enhanced Multi-threaded Slaves,即MTS),設定引數slave_parallel_workers>0並且global.slave_parallel_type=‘LOGICAL_CLOCK’,即可支援一個schema下,slave_parallel_workers個的worker執行緒併發執行relay log中主庫提交的事務。其核心思想:一個組提交的事務都是可以並行回放(配合binary log group commit);slave機器的relay log中 last_committed相同的事務(sequence_num不同)可以併發執行。其中,變數slave-parallel-type可以有兩個值:1)DATABASE 預設值,基於庫的並行複製方式;2)LOGICAL_CLOCK,基於組提交的並行複製方式;
MySQL 5.7開啟Enhanced Multi-Threaded Slave很簡單,只需要在Slave從資料庫的my.cnf檔案中如下配置即可:
# slave slave-parallel-type=LOGICAL_CLOCK slave-parallel-workers=8 #一般建議設定4-8,太多的執行緒會增加執行緒之間的同步開銷 master_info_repository=TABLE relay_log_info_repository=TABLE relay_log_recovery=ON
MySQL 5.7是基於組提交的並行複製,並且是支援"真正"的並行複製功能,這其中最為主要的原因:就是slave伺服器的回放與主機是一致的, 即master伺服器上是怎麼並行執行的slave上就怎樣進行並行回放。不再有庫的並行複製限制,對於二進位制日誌格式也無特殊的要求(基於庫的並行複製也沒有要求)。
MySQL5.7的並行複製,期望最大化還原主庫的並行度,實現方式是在binlog event中增加必要的資訊,以便slave節點根據這些資訊實現並行複製。MySQL5.7的並行複製建立在group commit的基礎上,所有在主庫上能夠完成prepared的語句表示沒有資料衝突,就可以在slave節點並行複製。
所以在並行複製環境中,除了在Slace從資料庫中配置之外,還需要在Master主資料庫上的my.cnf檔案中新增binlog_group_commit配置,否則從庫無法做到基於事物的並行複製:
binlog_group_commit_sync_delay = 100 binlog_group_commit_sync_no_delay_count = 10
binlog_group_commit_sync_delay,這個引數控制著日誌在刷盤前日誌提交要等待的時間,預設是0也就是說提交後立即刷盤,但是並不代表是關閉了組提交,當設定為0以上的時候,就允許多個事物的日誌同時間一起提交刷盤,也就是我們說的組提交。組提交是並行複製的基礎,我們設定這個值的大於0就代表開啟了組提交的延遲功能,而組提交是預設開啟的。最大值只能設定為1000000微妙。
binlog_group_commit_sync_no_delay_count ,這個參數列示我們在binlog_group_commit_sync_delay等待時間內,如果事物數達到這個引數的設定值,就會觸動一次組提交,如果這個值設為0的話就不會有任何的影響。如果到達時間但是事物數並沒有達到的話,也是會進行一次組提交操作的。
MySQL 5.7並行複製的思想簡單易懂,一言以蔽之: 一個組提交的事務都是可以並行回放 ,因為這些事務都已進入到事務的prepare階段,則說明事務之間沒有任何衝突(否則就不可能提交)。為了相容MySQL 5.6基於庫的並行複製,5.7引入了新的變數slave-parallel-type,其可以配置的值有:
- DATABASE:預設值,基於庫的並行複製方式
- LOGICAL_CLOCK:基於組提交的並行複製方式
支援並行複製的GTID
如何知道事務是否在一組中,又是一個問題,因為原版的MySQL並沒有提供這樣的資訊。在MySQL 5.7版本中,其設計方式是將組提交的資訊存放在GTID中。那麼如果使用者沒有開啟GTID功能,即將引數gtid_mode設定為OFF呢?故MySQL 5.7又引入了稱之為Anonymous_Gtid的二進位制日誌event型別,如:
mysql> SHOW BINLOG EVENTS in 'mysql-bin.000003'; +------------------+-----+----------------+-----------+-------------+-----------------------------------------------+ | Log_name | Pos | Event_type | Server_id | End_log_pos | Info | +------------------+-----+----------------+-----------+-------------+-----------------------------------------------+ | mysql-bin.000003 | 4 | Format_desc | 88 | 123 | Server ver: 5.7.7-rc-debug-log, Binlog ver: 4 | | mysql-bin.000003 | 123 | Previous_gtids | 88 | 194 | f11232f7-ff07-11e4-8fbb-00ff55e152c6:1-2 | | mysql-bin.000003 | 194 | Anonymous_Gtid | 88 | 259 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' | | mysql-bin.000003 | 259 | Query | 88 | 330 | BEGIN | | mysql-bin.000003 | 330 | Table_map | 88 | 373 | table_id: 108 (aaa.t) | | mysql-bin.000003 | 373 | Write_rows | 88 | 413 | table_id: 108 flags: STMT_END_F | ......
這意味著在 MySQL 5.7版本中即使不開啟GTID,每個事務開始前也是會存在一個Anonymous_Gtid ,而這GTID中就存在著組提交的資訊。
LOGICAL_CLOCK
然而,通過上述的SHOW BINLOG EVENTS,並沒有發現有關組提交的任何資訊。但是通過mysqlbinlog工具,使用者就能發現組提交的內部資訊:
如下檢視一個binlog日誌
root@localhost:~# mysqlbinlog mysql-bin.0000002 | grep last_committed #190112 17:45:16 server id 1 end_log_pos 219 CRC32 0xca2ee8c2 GTID last_committed=0 sequence_number=1 rbr_only=yes #190112 17:45:21 server id 1 end_log_pos 506 CRC32 0xe8047dd2 GTID last_committed=1 sequence_number=2 rbr_only=yes #190112 17:45:16 server id 1 end_log_pos 219 CRC32 0xca2ee8c2 GTID last_committed=2 sequence_number=3 rbr_only=yes #190112 17:45:21 server id 1 end_log_pos 506 CRC32 0xe8047dd2 GTID last_committed=3 sequence_number=4 rbr_only=yes
root@localhost:~# mysqlbinlog mysql-bin.0000006 | grep last_committed #150520 14:23:11 server id 88 end_log_pos 259 CRC32 0x4ead9ad6 GTID last_committed=0 sequence_number=1 #150520 14:23:11 server id 88 end_log_pos 1483 CRC32 0xdf94bc85 GTID last_committed=0 sequence_number=2 #150520 14:23:11 server id 88 end_log_pos 2708 CRC32 0x0914697b GTID last_committed=0 sequence_number=3 #150520 14:23:11 server id 88 end_log_pos 3934 CRC32 0xd9cb4a43 GTID last_committed=0 sequence_number=4 #150520 14:23:11 server id 88 end_log_pos 5159 CRC32 0x06a6f531 GTID last_committed=0 sequence_number=5 #150520 14:23:11 server id 88 end_log_pos 6386 CRC32 0xd6cae930 GTID last_committed=0 sequence_number=6 #150520 14:23:11 server id 88 end_log_pos 7610 CRC32 0xa1ea531c GTID last_committed=6 sequence_number=7 #150520 14:23:11 server id 88 end_log_pos 8834 CRC32 0x96864e6b GTID last_committed=6 sequence_number=8 #150520 14:23:11 server id 88 end_log_pos 10057 CRC32 0x2de1ae55 GTID last_committed=6 sequence_number=9 #150520 14:23:11 server id 88 end_log_pos 11280 CRC32 0x5eb13091 GTID last_committed=6 sequence_number=10 #150520 14:23:11 server id 88 end_log_pos 12504 CRC32 0x16721011 GTID last_committed=6 sequence_number=11 #150520 14:23:11 server id 88 end_log_pos 13727 CRC32 0xe2210ab6 GTID last_committed=6 sequence_number=12 #150520 14:23:11 server id 88 end_log_pos 14952 CRC32 0xf41181d3 GTID last_committed=12 sequence_number=13 ...
例如上述last_committed為0的事務有6個,這意味什麼呢?意味著這6個事物是作為一個組提交的,6個事物在perpare截斷獲取相同的last_committed而且相互不影響,最終是會作為一個組進行提交?,這就是所謂的組提交!上面表示組提交時提交了6個事務,而這6個事務在從機是可以進行並行回放的。
總之:MySQL 5.7推出的Enhanced Multi-Threaded Slave解決了困擾MySQL長達數十年的複製延遲問題,再次提醒一些無知的PostgreSQL使用者,不要再停留在之前對於MySQL的印象,物理複製也不一定肯定比邏輯複製有優勢,而MySQL 5.7的MTS已經完全可以解決延遲問題。總之, 5.7版本後,主從複製延遲問題將不存在!
基於GTID的並行複製環境部署記錄
1)在mysql-slave1從資料庫的my.cnf 檔案中新增下面MTS並行複製的配置 [root@mysql-slave1 ~]# vim /etc/my.cnf [mysqld] datadir = /var/lib/mysql socket = /var/lib/mysql/mysql.sock symbolic-links = 0 log-error = /var/log/mysqld.log pid-file = /var/run/mysqld/mysqld.pid #GTID: server_id = 2 gtid_mode = on enforce_gtid_consistency = on #binlog log_bin = mysql-bin log-slave-updates = 1 binlog_format = row sync-master-info = 1 sync_binlog = 1 #relay log skip_slave_start = 1 read_only = on #MTS slave-parallel-type = LOGICAL_CLOCK #開啟邏輯時鐘的複製 slave-parallel-workers = 4 #這裡設定執行緒數為4 (最大執行緒數不能超過16,即最大執行緒為16) master_info_repository = TABLE relay_log_info_repository = TABLE relay_log_recovery = on 配置完成後,記得重啟mysql服務 [root@mysql-slave1 ~]# systemctl restart mysqld 2)在mysql-master主資料庫的my.cnf 檔案中新增最後兩行配置 [root@mysql-master ~]# vim /etc/my.cnf [mysqld] datadir = /var/lib/mysql socket = /var/lib/mysql/mysql.sock symbolic-links = 0 log-error = /var/log/mysqld.log pid-file = /var/run/mysqld/mysqld.pid #GTID: server_id = 1 gtid_mode = on enforce_gtid_consistency = on #binlog log_bin = mysql-bin log-slave-updates = 1 binlog_format = row sync-master-info = 1 sync_binlog = 1 #relay log skip_slave_start = 1 #不配置binlog_group_commit從庫無法做到基於事物的並行複製 binlog_group_commit_sync_delay = 100 binlog_group_commit_sync_no_delay_count = 10 #為了資料安全再配置 sync_binlog=1 innodb_flush_log_at_trx_commit =1 #這個引數控制binlog寫入 磁碟的方式。設定為1時,表示每次commit;都寫入磁碟。這個重新整理的是redo log 即ib_logfile0,而不是binlog 配置完成後,記得重啟mysql服務 [root@mysql-master ~]# systemctl restart mysqld 登入mysql,檢視binlog_group_commit mysql> show variables like 'binlog_group_commit_%'; +-----------------------------------------+-------+ | Variable_name | Value | +-----------------------------------------+-------+ | binlog_group_commit_sync_delay | 100 | | binlog_group_commit_sync_no_delay_count | 10 | +-----------------------------------------+-------+ 2 rows in set (0.00 sec) 設定binlog_group_commit的上面兩個引數,否則從庫無法做到基於事物的並行複製! 這兩個引數共同決定了是否觸發組提交操作! 第二個參數列示該事務組提交之前總共等待累積到多少個事務(如上要累計到10個事務); 第一個引數則表示該事務組總共等待多長時間後進行提交(如上要總共等待100毫秒的時間),任何一個條件滿足則進行後續操作。 因為有這個等待,可以讓更多事務的binlog通過一次寫binlog檔案磁碟來完成提交,從而獲得更高的吞吐量。 3)登入mysql-slave1從資料庫 上面在配置並行複製後,主從資料庫的mysqld服務都重啟了,此時需要重啟從資料庫上的slave,這樣才能恢復正常的主從同步狀態! 記住:只要主資料庫的mysqld服務重啟,那麼從資料庫上就要重啟slave,以恢復主從同步狀態!!! mysql> show slave status \G; ........... ........... Slave_IO_Running: No Slave_SQL_Running: No mysql> stop slave; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> start slave; Query OK, 0 rows affected (0.10 sec) mysql> show slave status \G; .......... .......... Slave_IO_Running: Yes Slave_SQL_Running: Yes .......... Executed_Gtid_Set: 317e2aad-1565-11e9-9c2e-005056ac6820:1-11 Auto_Position: 1 這樣,mysql-slave1從資料庫就恢復了與mysql-master主資料庫的同步關係了 檢視優化項 mysql> use mysql; #切入到mysql庫 Database changed mysql> select * from slave_worker_info; #檢視slave_worker_info表 +----+---------------------------------+---------------+-------------------+----------------+---------------------------------+--------------------------+----------------------------+---------------------------+------------------+-----------------------+------------------------------------------------------------------+--------------+ | Id | Relay_log_name | Relay_log_pos | Master_log_name | Master_log_pos | Checkpoint_relay_log_name | Checkpoint_relay_log_pos | Checkpoint_master_log_name | Checkpoint_master_log_pos | Checkpoint_seqno | Checkpoint_group_size | Checkpoint_group_bitmap | Channel_name | +----+---------------------------------+---------------+-------------------+----------------+---------------------------------+--------------------------+----------------------------+---------------------------+------------------+-----------------------+------------------------------------------------------------------+--------------+ | 1 | ./mysql-slave1-relay-bin.000005 | 656 | mysql-bin.000008 | 481 | ./mysql-slave1-relay-bin.000005 | 369 | mysql-bin.000008 | 194 | 0 | 64 | | | | 2 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | | | 3 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | | | 4 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | | +----+---------------------------------+---------------+-------------------+----------------+---------------------------------+--------------------------+----------------------------+---------------------------+------------------+-----------------------+------------------------------------------------------------------+--------------+ 4 rows in set (0.00 sec) 以上可以檢視到,mysql庫下的slave_worker_info表下檢視到4個執行緒 也可以使用下面命令檢視執行緒數,這個跟在my.cnf檔案裡配置的是一樣的! mysql> show variables like '%slave_para%'; +------------------------+---------------+ | Variable_name | Value | +------------------------+---------------+ | slave_parallel_type | LOGICAL_CLOCK | | slave_parallel_workers | 4 | +------------------------+---------------+ 2 rows in set (0.00 sec) 4)同步複製測試 在mysql-master主資料庫插入新資料 mysql> insert into kevin.haha values(21,"caiyi"),(22,"manman"),(23,"titi"); Query OK, 3 rows affected (0.09 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> select * from kevin.haha; +----+---------+ | id | name | +----+---------+ | 4 | beijing | | 5 | hefei | | 10 | xihu | | 21 | caiyi | | 22 | manman | | 23 | titi | +----+---------+ 6 rows in set (0.00 sec) 然後在mysql-slave1從資料庫檢視,發現新資料已經同步過來了 mysql> select * from kevin.haha; +----+---------+ | id | name | +----+---------+ | 4 | beijing | | 5 | hefei | | 10 | xihu | | 21 | caiyi | | 22 | manman | | 23 | titi | +----+---------+ 6 rows in set (0.00 sec) 最後在mysql-master主資料庫上檢視組提交資訊 [root@mysql-master ~]# cd /var/lib/mysql [root@mysql-master mysql]# ll mysql-bin* -rw-r----- 1 mysql mysql 751 Jan 12 18:08 mysql-bin.000001 -rw-r----- 1 mysql mysql 1365 Jan 12 19:28 mysql-bin.000002 -rw-r----- 1 mysql mysql 1326 Jan 12 19:42 mysql-bin.000003 -rw-r----- 1 mysql mysql 57 Jan 12 19:28 mysql-bin.index [root@mysql-master mysql]# mysqlbinlog mysql-bin.000003 |grep last_committed #190112 19:37:06 server id 1 end_log_pos 259 CRC32 0x893c0ae8 GTID last_committed=0 sequence_number=1 rbr_only=yes #190112 19:37:12 server id 1 end_log_pos 542 CRC32 0xc36def61 GTID last_committed=1 sequence_number=2 rbr_only=yes #190112 19:42:42 server id 1 end_log_pos 825 CRC32 0x361701a2 GTID last_committed=2 sequence_number=3 rbr_only=yes #190112 19:42:48 server id 1 end_log_pos 1108 CRC32 0x8ba858c7 GTID last_committed=3 sequence_number=4 rbr_only=yes 如上,通過最新的binlog日誌看到,last_committed數值都不一樣,即沒有事務是在同一個組內提交的,也就是說這個日誌裡沒有組提交資訊。 這是因為沒有滿足binlog_grup_commit那兩個引數的條件,所以沒有進行組提交!
五、半同步複製
半同步複製: 預設情況下MySQL的複製是非同步的,master將新生成的binlog傳送給各slave後,無需等待slave的ack回覆(slave將接收到的binlog寫進relay log後才會回覆ack),直接就認為這次DDL/DML成功了, 半同步複製(semi-synchronous replication)是指master將新生成的binlog傳送給各slave時, 只需等待一個(預設)slave返回的ack資訊就返回成功。
MySQL 5.7對半同步複製作了大改進,新增了一個master執行緒。在MySQL 5.7以前,master上的binlog dump執行緒負責兩件事:dump日誌給slave的io_thread;接收來自slave的ack訊息。它們是序列方式工作的。在MySQL 5.7中,新增了一個專門負責接受ack訊息的執行緒ack collector thread。這樣master上有兩個執行緒獨立工作,可以同時傳送binlog到slave和接收slave的ack。還新增了幾個變數,其中最重要的是 rpl_semi_sync_master_wait_point ,它使得MySQL半同步複製有兩種工作模型。
半同步複製的兩種型別
從MySQL 5.7.2開始,MySQL支援兩種型別的半同步複製。這兩種型別由變數 rpl_semi_sync_master_wait_point (MySQL 5.7.2之前沒有該變數)控制,它有兩種值:AFTER_SYNC和AFTER_COMMIT。在MySQL 5.7.2之後,預設值為AFTER_SYNC,在此版本之前,等價的型別為AFTER_COMMIT。這個變數控制的是master何時提交、何時接收ack以及何時回覆成功資訊給客戶端的時間點。
AFTER_SYNC模式:master將新事務寫進binlog(buffer)後傳送給slave,再sync到自己的binlog file(disk), 之後才允許接收slave的ack回覆,接收到ack之後才會提交事務,並返回成功資訊給客戶端。
AFTER_COMMIT模式:master將新事務寫進binlog(buffer)後傳送給slave,再sync到自己的binlog file(disk),然後直接提交事務。之後才允許接收slave的ack回覆,然後再返回成功資訊給客戶端。
如下作圖,理解起來就容易了。(前提: 已經設定了sync_binlog=1,否則binlog刷盤時間由作業系統決定)
根據上面的圖解,接下來分析下這兩種模式的優缺點。
AFTER_SYNC
- 對於所有客戶端來說,它們看到的資料是一樣的,因為它們看到的資料都是在接收到slave的ack後提交後的資料。
- 這種模式下,如果master突然故障,不會丟失資料,因為所有成功的事務都已經寫進slave的relay log中了,slave的資料是最新的。
AFTER_COMMIT
- 不同客戶端看到的資料可能是不一樣的。對於發起事務請求的那個客戶端,它只有在master提交事務且收到slave的ack後才能看到提交的資料。但對於那些非本次事務的請求客戶端,它們在master提交後就能看到提交後的資料,這時候master可能還沒收到slave的ack。
- 如果master收到ack回覆前,slave和master都故障了,那麼將丟失這個事務中的資料。
在MySQL 5.7.2之前,等價的模式是 AFTER_COMMIT ,在此版本之後,預設的模式為 AFTER_SYNC ,該模式能最大程度地保證資料安全性,且效能上並不比 AFTER_COMMIT 差。
基於GTID的半同步複製環境部署記錄
Mysql 半同步複製配置可以參考: https://www.cnblogs.com/kevingrace/p/10228694.html 開啟半同步複製的方法有兩種: mysql命令列啟動; my.cnf檔案裡新增啟動配置; 推薦在my.cnf檔案裡新增半同步啟動配置方式 1) 配置mysql-master主資料庫上 my.cnf檔案,新增啟動半同步複製的配置 [root@mysql-master ~]# vim /etc/my.cnf [mysqld] datadir = /var/lib/mysql socket = /var/lib/mysql/mysql.sock symbolic-links = 0 log-error = /var/log/mysqld.log pid-file = /var/run/mysqld/mysqld.pid #GTID: server_id = 1 gtid_mode = on enforce_gtid_consistency = on #binlog log_bin = mysql-bin log-slave-updates = 1 binlog_format = row sync-master-info = 1 sync_binlog = 1 #relay log skip_slave_start = 1 #不配置binlog_group_commit從庫無法做到基於事物的並行複製 binlog_group_commit_sync_delay = 100 binlog_group_commit_sync_no_delay_count = 10 #為了資料安全再配置 sync_binlog=1 innodb_flush_log_at_trx_commit =1 #這個引數控制binlog寫入 磁碟的方式。設定為1時,表示每次commit;都寫入磁碟。這個重新整理的是redo log 即ib_logfile0,而不是binlog #開啟半同步複製 (超時時間為1s) plugin-load=rpl_semi_sync_master=semisync_master.so rpl_semi_sync_master_enabled = 1 rpl_semi_sync_master_timeout = 1000 配置完成後,記得重啟mysql服務 [root@mysql-master ~]# systemctl restart mysqld 2) 配置mysql-slave從資料庫上 my.cnf檔案,新增啟動半同步複製的配置 [root@mysql-slave1 ~]# vim /etc/my.cnf [mysqld] datadir = /var/lib/mysql socket = /var/lib/mysql/mysql.sock symbolic-links = 0 log-error = /var/log/mysqld.log pid-file = /var/run/mysqld/mysqld.pid #GTID: server_id = 2 gtid_mode = on enforce_gtid_consistency = on #binlog log_bin = mysql-bin log-slave-updates = 1 binlog_format = row sync-master-info = 1 sync_binlog = 1 #relay log skip_slave_start = 1 read_only = on #MTS slave-parallel-type = LOGICAL_CLOCK #開啟邏輯時鐘的複製 slave-parallel-workers = 4 #最大執行緒16 master_info_repository = TABLE relay_log_info_repository = TABLE relay_log_recovery = on # 開啟半同步複製 plugin-load=rpl_semi_sync_slave=semisync_slave.so rpl_semi_sync_slave_enabled=1 配置完成後,記得重啟mysql服務 [root@mysql-slave1 ~]# systemctl restart mysqld 3)在mysql-master主資料庫上載入 (前提是/usr/lib64/mysql/plugin/semisync_master.so 檔案存在。 一般mysql安裝後就預設產生) mysql> INSTALL PLUGIN rpl_semi_sync_master SONAME 'semisync_master.so'; Query OK, 0 rows affected (0.25 sec) 檢視外掛是否載入成功 mysql> SELECT PLUGIN_NAME, PLUGIN_STATUS FROM INFORMATION_SCHEMA.PLUGINS WHERE PLUGIN_NAME LIKE '%semi%'; +----------------------+---------------+ | PLUGIN_NAME | PLUGIN_STATUS | +----------------------+---------------+ | rpl_semi_sync_master | ACTIVE | +----------------------+---------------+ 1 row in set (0.00 sec) 檢視半同步是否在執行 mysql> show status like 'Rpl_semi_sync_master_status'; +-----------------------------+-------+ | Variable_name | Value | +-----------------------------+-------+ | Rpl_semi_sync_master_status | ON | +-----------------------------+-------+ 1 row in set (0.00 sec) 4)在mysql-slave1從資料庫上載入 (前提是/usr/lib64/mysql/plugin/semisync_slave.so 檔案存在。 一般mysql安裝後就預設產生) mysql> INSTALL PLUGIN rpl_semi_sync_slave SONAME 'semisync_slave.so'; Query OK, 0 rows affected (0.03 sec) 檢視外掛是否載入成功 mysql> SELECT PLUGIN_NAME, PLUGIN_STATUS FROM INFORMATION_SCHEMA.PLUGINS WHERE PLUGIN_NAME LIKE '%semi%'; +---------------------+---------------+ | PLUGIN_NAME | PLUGIN_STATUS | +---------------------+---------------+ | rpl_semi_sync_slave | ACTIVE | +---------------------+---------------+ 1 row in set (0.00 sec) 這個時候,檢視mysql-slave1的半同步是否執行 mysql> show status like 'Rpl_semi_sync_slave_status'; +----------------------------+-------+ | Variable_name | Value | +----------------------------+-------+ | Rpl_semi_sync_slave_status | OFF | +----------------------------+-------+ 1 row in set (0.01 sec) 發現還是OFF,明明已經在my.cnf檔案裡開啟了! 這是因為此時還沒有生效,必須從資料庫上的IO執行緒才能生產!!! mysql> STOP SLAVE IO_THREAD; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> START SLAVE IO_THREAD; Query OK, 0 rows affected (0.00 sec) 然後再檢視mysql-slave1的半同步狀態,發現就已經開啟了! mysql> show status like 'Rpl_semi_sync_slave_status'; +----------------------------+-------+ | Variable_name | Value | +----------------------------+-------+ | Rpl_semi_sync_slave_status | ON | +----------------------------+-------+ 1 row in set (0.00 sec) 檢視此時的主從同步狀態 mysql> show slave status \G; ........... ........... Slave_IO_Running: Yes Slave_SQL_Running: No 發現主從同步異常,這個時候再重啟下slave即可! mysql> stop slave; Query OK, 0 rows affected (0.06 sec) mysql> start slave; Query OK, 0 rows affected (0.10 sec) mysql> show slave status \G; ............ ............ Slave_IO_Running: Yes Slave_SQL_Running: Yes 5) 在mysql-master主資料庫上檢視 mysql> show status like '%Rpl_semi%'; +--------------------------------------------+-------+ | Variable_name | Value | +--------------------------------------------+-------+ | Rpl_semi_sync_master_clients | 1 | | Rpl_semi_sync_master_net_avg_wait_time | 0 | | Rpl_semi_sync_master_net_wait_time | 0 | | Rpl_semi_sync_master_net_waits | 0 | | Rpl_semi_sync_master_no_times | 0 | | Rpl_semi_sync_master_no_tx | 0 | | Rpl_semi_sync_master_status | ON | | Rpl_semi_sync_master_timefunc_failures | 0 | | Rpl_semi_sync_master_tx_avg_wait_time | 0 | | Rpl_semi_sync_master_tx_wait_time | 0 | | Rpl_semi_sync_master_tx_waits | 0 | | Rpl_semi_sync_master_wait_pos_backtraverse | 0 | | Rpl_semi_sync_master_wait_sessions | 0 | | Rpl_semi_sync_master_yes_tx | 0 | +--------------------------------------------+-------+ 14 rows in set (0.00 sec) 從上面資訊,發現Rpl_semi_sync_master_clients的數值為1,說明此時mysql-master主資料庫已經有一個半同步複製的從機,即mysql-slave1節點。 Rpl_semi_sync_master_yes_tx的數值為0, 說明此時還沒有半同步複製的sql語句被執行。 接著在mysql-master主資料庫上插入和更新資料,測試半同步複製 mysql> select * from kevin.haha; +----+---------+ | id | name | +----+---------+ | 4 | beijing | | 5 | hefei | | 10 | xihu | | 21 | caiyi | | 22 | manman | | 23 | titi | +----+---------+ 6 rows in set (0.01 sec) mysql> insert into kevin.haha values(30,"shikui"),(31,"shibo"),(32,"shijuan"); Query OK, 3 rows affected (0.15 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> update kevin.haha set id=8 where name="beijing"; Query OK, 1 row affected (0.22 sec) Rows matched: 1 Changed: 1 Warnings: 0 接著再去mysql-slave1從資料庫上檢視,發現新資料已經同步過來了 mysql> select * from kevin.haha; +----+---------+ | id | name | +----+---------+ | 5 | hefei | | 8 | beijing | | 10 | xihu | | 21 | caiyi | | 22 | manman | | 23 | titi | | 30 | shikui | | 31 | shibo | | 32 | shijuan | +----+---------+ 9 rows in set (0.00 sec) 接著再去mysql-master主資料庫上檢視,如下: mysql> show status like '%Rpl_semi%'; +--------------------------------------------+--------+ | Variable_name | Value | +--------------------------------------------+--------+ | Rpl_semi_sync_master_clients | 1 | | Rpl_semi_sync_master_net_avg_wait_time | 0 | | Rpl_semi_sync_master_net_wait_time | 0 | | Rpl_semi_sync_master_net_waits | 2 | | Rpl_semi_sync_master_no_times | 0 | | Rpl_semi_sync_master_no_tx | 0 | | Rpl_semi_sync_master_status | ON | | Rpl_semi_sync_master_timefunc_failures | 0 | | Rpl_semi_sync_master_tx_avg_wait_time | 133362 | | Rpl_semi_sync_master_tx_wait_time | 266725 | | Rpl_semi_sync_master_tx_waits | 2 | | Rpl_semi_sync_master_wait_pos_backtraverse | 0 | | Rpl_semi_sync_master_wait_sessions | 0 | | Rpl_semi_sync_master_yes_tx | 2 | +--------------------------------------------+--------+ 14 rows in set (0.01 sec) 從上面資訊可發現Rpl_semi_sync_master_yes_tx的數值為2,即發生了兩條半同步複製的sql語句,就是上面執行的那兩條(insert 和update) sql語句。
以上都是在mysql-master主資料庫和mysql-slave1從資料庫之間實現的基於GTID的主從複製、並行複製、半同步複製,即"一主一從"架構。 現在再把mysql-slave2的從節點新增進去,調整為"一主兩從"的同步架構。新增操作記錄如下:
1)在mysql-master主資料庫上操作 先新增同步許可權 mysql> grant replication slave,replication client on *.* to slave@'172.16.60.213' identified by "slave@123"; Query OK, 0 rows affected, 1 warning (0.14 sec) mysql> flush privileges; Query OK, 0 rows affected (0.14 sec) 備份主庫 [root@mysql-master ~]# mysqldump -u root -p'123456' --lock-all-tables --master-data=2 --flush-logs --all-databases --triggers --routines --events > 213_slave.sql 將備份檔案拷貝到mysql-slave2從資料庫上 [root@mysql-master ~]# rsync -e "ssh -p22" -avpgolr /root/213_slave.sql root@172.16.60.213:/root/ 記錄當前的gtid mysql> show global variables like 'gtid_%'; +----------------------------------+-------------------------------------------+ | Variable_name | Value | +----------------------------------+-------------------------------------------+ | gtid_executed | 317e2aad-1565-11e9-9c2e-005056ac6820:1-34 | | gtid_executed_compression_period | 1000 | | gtid_mode | ON | | gtid_owned | | | gtid_purged | 317e2aad-1565-11e9-9c2e-005056ac6820:1-16 | +----------------------------------+-------------------------------------------+ 5 rows in set (0.00 sec) 2)在mysql-slave2從資料庫上操作 首先在my.cnf檔案新增相關同步配置 (跟mysql-slave1從節點的my.cnf配置相比,除了將server_id修改為3之外,其他配置內容都一樣!) [root@mysql-slave2 ~]# cp /etc/my.cnf /etc/my.cnf.bak [root@mysql-slave2 ~]# >/etc/my.cnf [root@mysql-slave2 ~]# vim /etc/my.cnf [mysqld] datadir = /var/lib/mysql socket = /var/lib/mysql/mysql.sock symbolic-links = 0 log-error = /var/log/mysqld.log pid-file = /var/run/mysqld/mysqld.pid #GTID: server_id = 3 gtid_mode = on enforce_gtid_consistency = on #binlog log_bin = mysql-bin log-slave-updates = 1 binlog_format = row sync-master-info = 1 sync_binlog = 1 #relay log skip_slave_start = 1 read_only = on #MTS slave-parallel-type = LOGICAL_CLOCK #開啟邏輯時鐘的複製 slave-parallel-workers = 4 #最大執行緒16 master_info_repository = TABLE relay_log_info_repository = TABLE relay_log_recovery = on # 開啟半同步複製 plugin-load=rpl_semi_sync_slave=semisync_slave.so rpl_semi_sync_slave_enabled=1 配置完成後,不要忘記重啟mysql服務 [root@mysql-slave2 ~]# systemctl restart mysqld 恢復備份庫 [root@mysql-slave2 ~]# ll /root/213_slave.sql -rw-r--r-- 1 root root 805694 Jan 13 00:26 /root/213_slave.sql mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | +--------------------+ 4 rows in set (0.00 sec) mysql> source /root/213_slave.sql; mysql> select * from kevin.haha; +----+---------+ | id | name | +----+---------+ | 5 | hefei | | 8 | beijing | | 10 | xihu | | 21 | caiyi | | 22 | manman | | 23 | titi | | 30 | shikui | | 31 | shibo | | 32 | shijuan | +----+---------+ 9 rows in set (0.00 sec) 檢查一下mysql-slave2從資料庫上當前的gtid mysql> show global variables like 'gtid_%'; +----------------------------------+-------------------------------------------+ | Variable_name | Value | +----------------------------------+-------------------------------------------+ | gtid_executed | 317e2aad-1565-11e9-9c2e-005056ac6820:1-34 | | gtid_executed_compression_period | 1000 | | gtid_mode | ON | | gtid_owned | | | gtid_purged | 317e2aad-1565-11e9-9c2e-005056ac6820:1-34 | +----------------------------------+-------------------------------------------+ 5 rows in set (0.01 sec) 由於是從master-master主庫備份恢復過來的,所以此時mysql-slave2從資料庫的gtid和主庫的gtid是一樣的! 接著進行主從同步 mysql> stop slave; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> change master to master_host='172.16.60.211',master_user='slave',master_password='slave@123',master_auto_position=1; Query OK, 0 rows affected, 2 warnings (0.18 sec) mysql> start slave; Query OK, 0 rows affected (0.17 sec) ================================================================= 如果遇到報錯: ERROR 1872 (HY000): Slave failed to initialize relay log info structure from the repository 解決辦法: stop slave; reset slave; start slave; ================================================================= 檢視,發現主從同步正常 mysql> show slave status \G; ......... Slave_IO_Running: Yes Slave_SQL_Running: Yes 並行複製檢視 mysql> show variables like '%slave_para%'; +------------------------+---------------+ | Variable_name | Value | +------------------------+---------------+ | slave_parallel_type | LOGICAL_CLOCK | | slave_parallel_workers | 4 | +------------------------+---------------+ 2 rows in set (0.01 sec) mysql> select * from mysql.slave_worker_info; +----+----------------+---------------+-----------------+----------------+---------------------------+--------------------------+----------------------------+---------------------------+------------------+-----------------------+------------------------------------------------------------------+--------------+ | Id | Relay_log_name | Relay_log_pos | Master_log_name | Master_log_pos | Checkpoint_relay_log_name | Checkpoint_relay_log_pos | Checkpoint_master_log_name | Checkpoint_master_log_pos | Checkpoint_seqno | Checkpoint_group_size | Checkpoint_group_bitmap | Channel_name | +----+----------------+---------------+-----------------+----------------+---------------------------+--------------------------+----------------------------+---------------------------+------------------+-----------------------+------------------------------------------------------------------+--------------+ | 1 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | | | 2 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | | | 3 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | | | 4 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | | +----+----------------+---------------+-----------------+----------------+---------------------------+--------------------------+----------------------------+---------------------------+------------------+-----------------------+------------------------------------------------------------------+--------------+ 4 rows in set (0.00 sec) 接著在mysql-slave2從資料庫上開啟半同步 mysql> INSTALL PLUGIN rpl_semi_sync_slave SONAME 'semisync_slave.so'; Query OK, 0 rows affected (0.03 sec) mysql> SELECT PLUGIN_NAME, PLUGIN_STATUS FROM INFORMATION_SCHEMA.PLUGINS WHERE PLUGIN_NAME LIKE '%semi%'; +---------------------+---------------+ | PLUGIN_NAME | PLUGIN_STATUS | +---------------------+---------------+ | rpl_semi_sync_slave | ACTIVE | +---------------------+---------------+ 1 row in set (0.00 sec) mysql> STOP SLAVE IO_THREAD; Query OK, 0 rows affected (0.02 sec) mysql> START SLAVE IO_THREAD; Query OK, 0 rows affected (0.00 sec) mysql> show status like 'Rpl_semi_sync_slave_status'; +----------------------------+-------+ | Variable_name | Value | +----------------------------+-------+ | Rpl_semi_sync_slave_status | ON | +----------------------------+-------+ 1 row in set (0.00 sec) 3) 現在回到mysql-master主資料庫檢視 mysql> show slave hosts; +-----------+------+------+-----------+--------------------------------------+ | Server_id | Host | Port | Master_id | Slave_UUID | +-----------+------+------+-----------+--------------------------------------+ | 3 | | 3306 | 1 | 2658b203-1565-11e9-9f8b-005056880888 | | 2 | | 3306 | 1 | 2c1efc46-1565-11e9-ab8e-00505688047c | +-----------+------+------+-----------+--------------------------------------+ 2 rows in set (0.00 sec) 如上資訊可知mysql-master主資料庫現在有兩個從資料庫,分別為mysql-slave1 和 mysql-slave2 mysql> show status like '%Rpl_semi%'; +--------------------------------------------+--------+ | Variable_name | Value | +--------------------------------------------+--------+ | Rpl_semi_sync_master_clients | 2 | | Rpl_semi_sync_master_net_avg_wait_time | 0 | | Rpl_semi_sync_master_net_wait_time | 0 | | Rpl_semi_sync_master_net_waits | 4 | | Rpl_semi_sync_master_no_times | 0 | | Rpl_semi_sync_master_no_tx | 0 | | Rpl_semi_sync_master_status | ON | | Rpl_semi_sync_master_timefunc_failures | 0 | | Rpl_semi_sync_master_tx_avg_wait_time | 98077 | | Rpl_semi_sync_master_tx_wait_time | 392310 | | Rpl_semi_sync_master_tx_waits | 4 | | Rpl_semi_sync_master_wait_pos_backtraverse | 0 | | Rpl_semi_sync_master_wait_sessions | 0 | | Rpl_semi_sync_master_yes_tx | 4 | +--------------------------------------------+--------+ 14 rows in set (0.00 sec) 如上資訊可知,mysql-master主資料庫現在有兩個半同步複製的從庫,即mysql-slave1 和mysql-slave2 4)現在測試下同步效果 在mysql-master主資料庫上更新資料 mysql> delete from kevin.haha where id>10; Query OK, 6 rows affected (0.20 sec) mysql> insert into kevin.haha values(11,"changping"),(12,"wangjing"); Query OK, 2 rows affected (0.38 sec) Records: 2 Duplicates: 0 Warnings: 0 在mysql-slave1從資料庫檢視,發現已經同步過來了 mysql> select * from kevin.haha; +----+-----------+ | id | name | +----+-----------+ | 5 | hefei | | 8 | beijing | | 10 | xihu | | 11 | changping | | 12 | wangjing | +----+-----------+ 5 rows in set (0.00 sec) 在mysql-slave2從資料庫檢視,發現已經同步過來了 mysql> select * from kevin.haha; +----+-----------+ | id | name | +----+-----------+ | 5 | hefei | | 8 | beijing | | 10 | xihu | | 11 | changping | | 12 | wangjing | +----+-----------+ 5 rows in set (0.00 sec)
到此,已經完成了Mysql5.7"一主兩從"架構上基於GTID主從複製+並行複製+增強半同步複製環境,下面再說下讀寫分離環境:
六、讀寫分離 (MySQL ProxySQL)
ProxySQL是用C++語言開發的,也是percona推的一款中介軟體,雖然也是一個輕量級產品,但效能很好(據測試,能處理千億級的資料),功能也足夠,能滿足中介軟體所需的絕大多數功能,包括:
- 最基本的讀寫分離,且安裝起來也十分方便。
- 可定製基於使用者、基於schema、基於語句的規則對SQL語句進行路由。換句話說,規則很靈活。基於schema和與語句級的規則,可以實現簡單的sharding。
- 可快取查詢結果。雖然ProxySQL的快取策略比較簡陋,但實現了基本的快取功能,絕大多數時候也夠用了。此外,作者已經打算實現更豐富的快取策略。
- 監控後端節點。ProxySQL可以監控後端節點的多個指標,包括:ProxySQL和後端的心跳資訊,後端節點的read-only/read-write,slave和master的資料同步延遲性(replication lag)。
ProxySQL是一個能實實在在用在生產環境的MySQL中介軟體,可以實現讀寫分離,支援 Query 路由功能,支援動態指定某個 SQL 進行 cache,支援動態載入配置、故障切換和一些 SQL的過濾功能。還有一些同類產品比如 DBproxy、MyCAT、OneProxy 等。但經過反覆對比和測試之後,還是覺得ProxySQL是一款效能不諳,靠譜穩定的MySQL 中介軟體產品 !
ProxySQL讀寫分離環境部署記錄
下面操作是在mysql-proxy代理層節點上完成的(需要注意: 兩個從庫都要開啟 read_only=on):
1)先在本機安裝mysql客戶端,用於在本機連線到ProxySQL的管理介面
[root@mysql-proxy ~]# vim /etc/yum.repos.d/mariadb.repo [mariadb] name = MariaDB baseurl = http://yum.mariadb.org/10.3.5/centos6-amd64 gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB gpgcheck=1 安裝mysql-clinet客戶端 [root@mysql-proxy ~]# yum install -y MariaDB-client ================================================= 如果遇到報錯: Error: MariaDB-compat conflicts with 1:mariadb-libs-5.5.60-1.el7_5.x86_64 You could try using --skip-broken to work around the problem You could try running: rpm -Va --nofiles --nodigest 解決辦法: [root@mysql-proxy ~]# rpm -qa|grep mariadb* mariadb-libs-5.5.56-2.el7.x86_64 [root@mysql-proxy ~]# rpm -e mariadb-libs-5.5.56-2.el7.x86_64 --nodeps [root@mysql-proxy ~]# yum install -y MariaDB-client
2)安裝ProxySQL (中文安裝手冊: https://github.com/malongshuai/proxysql/wiki)
[root@mysql-proxy ~]# vim /etc/yum.repos.d/proxysql.repo [proxysql_repo] name= ProxySQL YUM repository baseurl=http://repo.proxysql.com/ProxySQL/proxysql-1.4.x/centos/\$releasever gpgcheck=1 gpgkey=http://repo.proxysql.com/ProxySQL/repo_pub_key 執行安裝 [root@mysql-proxy ~]# yum -y install proxysql [root@mysql-proxy ~]# proxysql --version ProxySQL version 1.4.13-15-g69d4207, codename Truls 啟動ProxySQL [root@mysql-proxy ~]# chkconfig proxysql on [root@mysql-proxy ~]# systemctl start proxysql [root@mysql-proxy ~]# systemctl status proxysql 啟動後會監聽兩個埠, 預設為6032和6033。6032埠是ProxySQL的管理埠,6033是ProxySQL對外提供服務的埠 (即連線到轉發後端的真正資料庫的轉發埠)。 [root@mysql-proxy ~]# netstat -tunlp Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:6032 0.0.0.0:* LISTEN 23940/proxysql tcp 0 0 0.0.0.0:6033 0.0.0.0:* LISTEN 23940/proxysql
3)向ProxySQL中新增MySQL節點
ProxySQL也是有管理介面和客戶端介面,通過配置檔案/etc/proxysql.cnf可以看到管理和客戶端介面的資訊. [root@mysql-proxy ~]# cat /etc/proxysql.cnf ......... admin_variables= { admin_credentials="admin:admin" # mysql_ifaces="127.0.0.1:6032;/tmp/proxysql_admin.sock" mysql_ifaces="0.0.0.0:6032" # refresh_interval=2000 # debug=true } mysql_variables= { threads=4 max_connections=2048 default_query_delay=0 default_query_timeout=36000000 have_compress=true poll_timeout=2000 # interfaces="0.0.0.0:6033;/tmp/proxysql.sock" interfaces="0.0.0.0:6033" default_schema="information_schema" stacksize=1048576 server_version="5.5.30" connect_timeout_server=3000 .......... 通過上面,可以看到管理介面的埠是6032,賬號密碼是admin(可以動態修改),允許客戶端連線, 客戶端介面的埠是6033,賬號密碼通過管理介面去設定。 在mysql-proxy本機使用mysql客戶端連線到ProxySQL的管理介面(admin interface), 該介面的預設管理員使用者和密碼都是admin. 下面是通過管理埠6032去連線的(下面連線命令中後面的--prompt 'admin'欄位可以不加,也是可以登入進去的) [root@mysql-proxy ~]# mysql -uadmin -padmin -P6032 -h127.0.0.1 --prompt 'admin> ' Welcome to the MariaDB monitor. Commands end with ; or \g. Your MySQL connection id is 8 Server version: 5.5.30 (ProxySQL Admin Module) Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. admin> show databases; +-----+---------------+-------------------------------------+ | seq | name | file | +-----+---------------+-------------------------------------+ | 0 | main | | | 2 | disk | /var/lib/proxysql/proxysql.db | | 3 | stats | | | 4 | monitor | | | 5 | stats_history | /var/lib/proxysql/proxysql_stats.db | +-----+---------------+-------------------------------------+ 5 rows in set (0.001 sec) ProxySQL提供了幾個庫,每個庫都有各自的意義; - main 記憶體配置資料庫,表裡存放後端db例項、使用者驗證、路由規則等資訊。表名以 runtime_開頭的表示proxysql當前執行的配置內容, 不能通過dml語句修改,只能修改對應的不以 runtime_ 開頭的(在記憶體)裡的表,然後 LOAD 使其生效, SAVE 使其存到硬碟以供下次重啟載入。 - disk 是持久化到硬碟的配置,sqlite資料檔案。 - stats 是proxysql執行抓取的統計資訊,包括到後端各命令的執行次數、流量、processlist、查詢種類彙總/執行時間等等。 - monitor 庫儲存 monitor 模組收集的資訊,主要是對後端db的健康/延遲檢查。 主要注意main和monitor資料庫中的表 admin> show tables from main; +--------------------------------------------+ | tables | +--------------------------------------------+ | global_variables | | mysql_collations | | mysql_group_replication_hostgroups | | mysql_query_rules | | mysql_query_rules_fast_routing | | mysql_replication_hostgroups | | mysql_servers | | mysql_users | | proxysql_servers | | runtime_checksums_values | | runtime_global_variables | | runtime_mysql_group_replication_hostgroups | | runtime_mysql_query_rules | | runtime_mysql_query_rules_fast_routing | | runtime_mysql_replication_hostgroups | | runtime_mysql_servers | | runtime_mysql_users | | runtime_proxysql_servers | | runtime_scheduler | | scheduler | +--------------------------------------------+ 20 rows in set (0.001 sec) 幾個重要欄位含義: global_variables 設定變數,包括監聽的埠、管理賬號等。 mysql_collations 相關字符集和校驗規則。 mysql_query_rules 定義查詢路由規則。 admin> show tables from monitor; +------------------------------------+ | tables | +------------------------------------+ | mysql_server_connect_log | | mysql_server_group_replication_log | | mysql_server_ping_log | | mysql_server_read_only_log | | mysql_server_replication_lag_log | +------------------------------------+ 5 rows in set (0.000 sec) runtime_開頭的是執行時的配置,這些是不能修改的。要修改ProxySQL的配置,需要修改了非runtime_表,修改後必須執行LOAD ... TO RUNTIME 才能載入到RUNTIME生效,執行save ... to disk才能將配置持久化儲存到磁碟。 使用insert語句新增主機到mysql_servers表中,其中:hostgroup_id 10 表示寫組,20表示讀組。 admin> insert into mysql_servers(hostgroup_id,hostname,port) values(10,'172.16.60.211',3306); Query OK, 1 row affected (0.001 sec) admin> insert into mysql_servers(hostgroup_id,hostname,port) values(10,'172.16.60.212',3306); Query OK, 1 row affected (0.000 sec) admin> insert into mysql_servers(hostgroup_id,hostname,port) values(10,'172.16.60.213',3306); Query OK, 1 row affected (0.000 sec) 檢視這3個節點是否插入成功,以及它們的狀態。 admin> select * from mysql_servers\G; *************************** 1. row *************************** hostgroup_id: 10 hostname: 172.16.60.211 port: 3306 status: ONLINE weight: 1 compression: 0 max_connections: 1000 max_replication_lag: 0 use_ssl: 0 max_latency_ms: 0 comment: *************************** 2. row *************************** hostgroup_id: 10 hostname: 172.16.60.212 port: 3306 status: ONLINE weight: 1 compression: 0 max_connections: 1000 max_replication_lag: 0 use_ssl: 0 max_latency_ms: 0 comment: *************************** 3. row *************************** hostgroup_id: 10 hostname: 172.16.60.213 port: 3306 status: ONLINE weight: 1 compression: 0 max_connections: 1000 max_replication_lag: 0 use_ssl: 0 max_latency_ms: 0 comment: 3 rows in set (0.000 sec) ERROR: No query specified admin> 如上修改後,載入到RUNTIME,並儲存到disk admin> load mysql servers to runtime; Query OK, 0 rows affected (0.005 sec) admin> save mysql servers to disk; Query OK, 0 rows affected (0.468 sec)
4)監控後端MySQL節點
如上新增Mysql節點之後,還需要監控這些後端節點。對於後端是主從複製的環境來說,這是必須的,因為ProxySQL需要通過每個節點的read_only值來自動調整 它們是屬於讀組還是寫組。 首先在後端master主資料節點上建立一個用於監控的使用者名稱(只需在master上建立即可,因為會複製到slave上),這個使用者名稱只需具有USAGE許可權即可。如果還需 要監控複製結構中slave是否嚴重延遲於master(這個俗語叫做"拖後腿",術語叫做"replication lag"),則還需具備replication client許可權。 即在mysql-master主資料庫節點行執行: mysql> create user monitor@'172.16.60.%' identified by 'P@ssword1!'; Query OK, 0 rows affected (0.08 sec) mysql> grant replication client on *.* to monitor@'172.16.60.%'; Query OK, 0 rows affected (0.07 sec) mysql> flush privileges; Query OK, 0 rows affected (0.07 sec) 然後回到mysql-proxy代理層節點上配置監控 admin> set mysql-monitor_username='monitor'; Query OK, 1 row affected (0.001 sec) admin> set mysql-monitor_password='P@ssword1!'; Query OK, 1 row affected (0.000 sec) 修改後,載入到RUNTIME,並儲存到disk admin> load mysql variables to runtime; Query OK, 0 rows affected (0.001 sec) admin> save mysql variables to disk; Query OK, 96 rows affected (0.180 sec) 驗證監控結果:ProxySQL監控模組的指標都儲存在monitor庫的log表中。 以下是連線是否正常的監控(對connect指標的監控):(在前面可能會有很多connect_error,這是因為沒有配置監控資訊時的錯誤, 配置後如果connect_error的結果為NULL則表示正常) admin> select * from mysql_server_connect_log; +---------------+------+------------------+-------------------------+------------------------------------------------------------------------+ | hostname | port | time_start_us | connect_success_time_us | connect_error | +---------------+------+------------------+-------------------------+------------------------------------------------------------------------+ | 172.16.60.213 | 3306 | 1547436747566683 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.211 | 3306 | 1547436748167350 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547436748767837 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547436807566915 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.211 | 3306 | 1547436808112262 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.213 | 3306 | 1547436808657603 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.213 | 3306 | 1547436867566829 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.211 | 3306 | 1547436868151063 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547436868735236 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547436927567060 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.211 | 3306 | 1547436928247532 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.213 | 3306 | 1547436928927772 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.211 | 3306 | 1547436987567058 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547436988049160 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.213 | 3306 | 1547436988531003 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.212 | 3306 | 1547437047567194 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.213 | 3306 | 1547437048132480 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.211 | 3306 | 1547437048697765 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.211 | 3306 | 1547437107567258 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547437108310411 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.213 | 3306 | 1547437109053480 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.213 | 3306 | 1547437167567303 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.211 | 3306 | 1547437168158076 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547437168748763 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.213 | 3306 | 1547437227567525 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.211 | 3306 | 1547437228288921 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547437229010153 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.211 | 3306 | 1547437287567412 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547437288343609 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.213 | 3306 | 1547437289119851 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.213 | 3306 | 1547437295397678 | 1388 | NULL | | 172.16.60.211 | 3306 | 1547437295826682 | 1377 | NULL | | 172.16.60.212 | 3306 | 1547437296255659 | 8072 | NULL | +---------------+------+------------------+-------------------------+------------------------------------------------------------------------+ 33 rows in set (0.001 sec) 以下是對心跳資訊的監控(對ping指標的監控) admin> select * from mysql_server_ping_log; +---------------+------+------------------+----------------------+------------------------------------------------------------------------+ | hostname | port | time_start_us | ping_success_time_us | ping_error | +---------------+------+------------------+----------------------+------------------------------------------------------------------------+ | 172.16.60.213 | 3306 | 1547436798804839 | 0 | Access denied for user 'monitor'@'172.16.60.213' (using password: YES) | | 172.16.60.211 | 3306 | 1547436798875555 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547436798946212 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.213 | 3306 | 1547436808804803 | 0 | Access denied for user 'monitor'@'172.16.60.213' (using password: YES) | | 172.16.60.212 | 3306 | 1547436808931415 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.211 | 3306 | 1547436809058082 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | .................... .................... | 172.16.60.213 | 3306 | 1547437295030407 | 335 | NULL | | 172.16.60.211 | 3306 | 1547437295159540 | 218 | NULL | | 172.16.60.212 | 3306 | 1547437295288638 | 172 | NULL | | 172.16.60.211 | 3306 | 1547437365241682 | 337 | NULL | | 172.16.60.211 | 3306 | 1547437375031403 | 435 | NULL | .................. .................. | 172.16.60.213 | 3306 | 1547437395160777 | 469 | NULL | | 172.16.60.211 | 3306 | 1547437395289919 | 377 | NULL | +---------------+------+------------------+----------------------+------------------------------------------------------------------------+ 183 rows in set (0.001 sec) 但是,read_only和replication_lag的監控日誌都為空。 admin> select * from mysql_server_read_only_log; Empty set (0.000 sec) admin> select * from mysql_server_replication_lag_log; Empty set (0.000 sec) 例如,指定寫組的id為10,讀組的id為20。 admin> insert into mysql_replication_hostgroups values(10,20,1); Query OK, 1 row affected (0.000 sec) 在該配置載入到RUNTIME生效之前,先檢視下各mysql server所在的組。 admin> select hostgroup_id,hostname,port,status,weight from mysql_servers; +--------------+---------------+------+--------+--------+ | hostgroup_id | hostname | port | status | weight | +--------------+---------------+------+--------+--------+ | 10 | 172.16.60.211 | 3306 | ONLINE | 1 | | 10 | 172.16.60.212 | 3306 | ONLINE | 1 | | 10 | 172.16.60.213 | 3306 | ONLINE | 1 | +--------------+---------------+------+--------+--------+ 3 rows in set (0.000 sec) 3個節點都在hostgroup_id=10的組中。 現在,將剛才mysql_replication_hostgroups表的修改載入到RUNTIME生效。 admin> load mysql servers to runtime; Query OK, 0 rows affected (0.005 sec) admin> save mysql servers to disk; Query OK, 0 rows affected (0.406 sec) 一載入,Monitor模組就會開始監控後端的read_only值,當監控到read_only值後,就會按照read_only的值將某些節點自動移動到讀/寫組。 例如,此處所有節點都在id=10的寫組,slave1和slave2都是slave,它們的read_only=1,這兩個節點將會移動到id=20的組。 如果一開始這3節點都在id=20的讀組,那麼移動的將是Master節點,會移動到id=10的寫組。 現在看結果 admin> select hostgroup_id,hostname,port,status,weight from mysql_servers; +--------------+---------------+------+--------+--------+ | hostgroup_id | hostname | port | status | weight | +--------------+---------------+------+--------+--------+ | 10 | 172.16.60.211 | 3306 | ONLINE | 1 | | 20 | 172.16.60.212 | 3306 | ONLINE | 1 | | 20 | 172.16.60.213 | 3306 | ONLINE | 1 | +--------------+---------------+------+--------+--------+ 3 rows in set (0.000 sec) admin> select * from mysql_server_read_only_log; +---------------+------+------------------+-----------------+-----------+-------+ | hostname | port | time_start_us | success_time_us | read_only | error | +---------------+------+------------------+-----------------+-----------+-------+ | 172.16.60.212 | 3306 | 1547438982938183 | 694 | 1 | NULL | | 172.16.60.211 | 3306 | 1547438982950903 | 741 | 0 | NULL | .............. .............. | 172.16.60.211 | 3306 | 1547439054961006 | 517 | 0 | NULL | | 172.16.60.213 | 3306 | 1547439054977658 | 479 | 1 | NULL | +---------------+------+------------------+-----------------+-----------+-------+ 147 rows in set (0.001 sec)
5)配置mysql_users
上面的所有配置都是關於後端MySQL節點的,現在可以配置關於SQL語句的,包括:傳送SQL語句的使用者、SQL語句的路由規則、SQL查詢的快取、 SQL語句的重寫等等。本小節是SQL請求所使用的使用者配置,例如root使用者。這要求我們需要先在後端MySQL節點新增好相關使用者。這裡以root和 sqlsender兩個使用者名稱為例。 首先,在mysql-master主資料庫節點上執行:(只需master執行即可,會複製給兩個slave) mysql> grant all on *.* to root@'172.16.60.%' identified by 'passwd'; Query OK, 0 rows affected, 1 warning (0.06 sec) mysql> grant all on *.* to sqlsender@'172.16.60.%' identified by 'P@ssword1!'; Query OK, 0 rows affected, 1 warning (0.15 sec) mysql> flush privileges; Query OK, 0 rows affected (0.06 sec) 然後回到mysql-proxy代理層節點,配置mysql_users表,將剛才的兩個使用者新增到該表中。 admin> insert into mysql_users(username,password,default_hostgroup) values('root','passwd',10); Query OK, 1 row affected (0.001 sec) admin> insert into mysql_users(username,password,default_hostgroup) values('sqlsender','P@ssword1!',10); Query OK, 1 row affected (0.000 sec) admin> load mysql users to runtime; Query OK, 0 rows affected (0.001 sec) admin> save mysql users to disk; Query OK, 0 rows affected (0.108 sec) mysql_users表有不少欄位,最主要的三個欄位為username、password和default_hostgroup: - username:前端連線ProxySQL,以及ProxySQL將SQL語句路由給MySQL所使用的使用者名稱。 - password:使用者名稱對應的密碼。可以是明文密碼,也可以是hash密碼。如果想使用hash密碼,可以先在某個MySQL節點上執行 select password(PASSWORD),然後將加密結果複製到該欄位。 - default_hostgroup:該使用者名稱預設的路由目標。例如,指定root使用者的該欄位值為10時,則使用root使用者傳送的SQL語句預設 情況下將路由到hostgroup_id=10組中的某個節點。 admin> select * from mysql_users\G *************************** 1. row *************************** username: root password: passwd active: 1 use_ssl: 0 default_hostgroup: 10 default_schema: NULL schema_locked: 0 transaction_persistent: 1 fast_forward: 0 backend: 1 frontend: 1 max_connections: 10000 *************************** 2. row *************************** username: sqlsender password: P@ssword1! active: 1 use_ssl: 0 default_hostgroup: 10 default_schema: NULL schema_locked: 0 transaction_persistent: 1 fast_forward: 0 backend: 1 frontend: 1 max_connections: 10000 2 rows in set (0.000 sec) 雖然這裡沒有詳細介紹mysql_users表,但上面標註了"注意本行"的兩個欄位必須要引起注意。只有active=1的使用者才是有效的使用者。 至於transaction_persistent欄位,當它的值為1時,表示事務持久化:當某連線使用該使用者開啟了一個事務後,那麼在事務提交/回滾之前, 所有的語句都路由到同一個組中,避免語句分散到不同組。在以前的版本中,預設值為0,不知道從哪個版本開始,它的預設值為1。 我們期望的值為1,所以在繼續下面的步驟之前,先檢視下這個值,如果為0,則執行下面的語句修改為1。 admin> update mysql_users set transaction_persistent=1 where username='root'; Query OK, 1 row affected (0.000 sec) admin> update mysql_users set transaction_persistent=1 where username='sqlsender'; Query OK, 1 row affected (0.000 sec) admin> load mysql users to runtime; Query OK, 0 rows affected (0.001 sec) admin> save mysql users to disk; Query OK, 0 rows affected (0.098 sec) 然後,另開一個終端,分別使用root使用者和sqlsender使用者測試下它們是否能路由到預設的hostgroup_id=10(它是一個寫組)讀、寫資料。 [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e "select @@server_id" #這是通過轉發埠6033連線的,連線的是轉發到後端真正的資料庫! +-------------+ | @@server_id | +-------------+ | 1 | +-------------+ [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e "create database proxy_test" [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e "show databases;" +--------------------+ | Database | +--------------------+ | information_schema | | kevin | | mysql | | performance_schema | | proxy_test | | sys | +--------------------+ [root@mysql-proxy ~]# mysql -usqlsender -pP@ssword1! -P6033 -h127.0.0.1 -e 'use proxy_test;create table t(id int);' [root@mysql-proxy ~]# mysql -usqlsender -pP@ssword1! -P6033 -h127.0.0.1 -e 'show tables from proxy_test;' +----------------------+ | Tables_in_proxy_test | +----------------------+ | t | +----------------------+
6)讀寫分離:配置路由規則
ProxySQL的路由規則非常靈活,可以基於使用者、基於schema以及基於每個語句實現路由規則的定製。本案例作為一個入門配置,實現一個最簡單的語句級路由規則,從而實現讀寫分離。 必須注意,這只是實驗,實際的路由規則絕不應該僅根據所謂的讀、寫操作進行分離,而是從各項指標中找出壓力大、執行頻繁的語句單獨寫規則、做快取等等。和查詢規則有關的表有兩個: mysql_query_rules和mysql_query_rules_fast_routing,後者是前者的擴充套件表,1.4.7之後才支援該快速路由表。本案例只介紹第一個表。插入兩個規則,目的是將select語句分離到 hostgroup_id=20的讀組,但由於select語句中有一個特殊語句SELECT...FOR UPDATE它會申請寫鎖,所以應該路由到hostgroup_id=10的寫組。 admin> insert into mysql_query_rules(rule_id,active,match_digest,destination_hostgroup,apply) VALUES (1,1,'^SELECT.*FOR UPDATE$',10,1), (2,1,'^SELECT',20,1); Query OK, 2 rows affected (0.001 sec) admin> load mysql query rules to runtime; Query OK, 0 rows affected (0.000 sec) admin> save mysql query rules to disk; Query OK, 0 rows affected (0.179 sec) 需要注意: select ... for update規則的rule_id必須要小於普通的select規則的rule_id,因為ProxySQL是根據rule_id的順序進行規則匹配的。 再來測試下,讀操作是否路由給了hostgroup_id=20的讀組。 [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e 'select @@server_id' +-------------+ | @@server_id | +-------------+ | 3 | +-------------+ [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e 'select @@server_id' +-------------+ | @@server_id | +-------------+ | 2 | +-------------+ 讀操作已經路由給讀組,再看看寫操作。這裡以事務持久化進行測試。 [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e 'start transaction;select @@server_id;commit;select @@server_id;' +-------------+ | @@server_id | +-------------+ | 1 | +-------------+ +-------------+ | @@server_id | +-------------+ | 3 | +-------------+ 顯然,一切都按照預期進行。最後,如果想檢視路由的資訊,可查詢stats庫中的stats_mysql_query_digest表。 以下是該表的一個輸出格式示例(和本案例無關)。 admin> SELECT hostgroup hg, sum_time, count_star, digest_text FROM stats_mysql_query_digest ORDER BY sum_time DESC; +----+----------+------------+----------------------------------+ | hg | sum_time | count_star | digest_text | +----+----------+------------+----------------------------------+ | 10 | 236771 | 1 | create table t(id int) | | 10 | 53767 | 1 | create database proxy_test | | 20 | 10344 | 1 | select @@server_id | | 20 | 3350 | 3 | select @@server_id | | 10 | 2469 | 2 | SELECT DATABASE() | | 10 | 1678 | 2 | select @@server_id | | 10 | 1193 | 1 | show databases | | 10 | 1191 | 1 | start transaction | | 10 | 815 | 1 | show tables from proxy_test | | 10 | 289 | 1 | reate table t(id int) | | 10 | 162 | 1 | commit | | 10 | 0 | 6 | select @@version_comment limit ? | | 10 | 0 | 4 | select @@version_comment limit ? | | 10 | 0 | 1 | select @@version_comment limit ? | +----+----------+------------+----------------------------------+ 14 rows in set (0.002 sec)
7)最後測試通過proxysql外掛進行讀寫分離
mysql-master主資料庫檢視 mysql> select * from kevin.haha; +----+-----------+ | id | name | +----+-----------+ | 5 | hefei | | 8 | beijing | | 10 | xihu | | 11 | changping | | 12 | wangjing | +----+-----------+ 5 rows in set (0.00 sec) mysql-slave1和mysql-slave2兩個從資料庫檢視 mysql> select * from kevin.haha; +----+-----------+ | id | name | +----+-----------+ | 5 | hefei | | 8 | beijing | | 10 | xihu | | 11 | changping | | 12 | wangjing | +----+-----------+ 5 rows in set (0.00 sec) 在mysql-proxy代理層節點,通過proxysql進行資料寫入,並檢視 [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e 'insert into kevin.haha values(21,"zhongguo"),(22,"xianggang"),(23,"taiwan");' [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e 'delete from kevin.haha where id=10' [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e 'select * from kevin.haha;' +----+-----------+ | id | name | +----+-----------+ | 5 | hefei | | 8 | beijing | | 11 | changping | | 12 | wangjing | | 21 | zhongguo | | 22 | xianggang | | 23 | taiwan | 在mysql-master主資料庫節點檢視 mysql> select * from kevin.haha; +----+-----------+ | id | name | +----+-----------+ | 5 | hefei | | 8 | beijing | | 11 | changping | | 12 | wangjing | | 21 | zhongguo | | 22 | xianggang | | 23 | taiwan | +----+-----------+ 7 rows in set (0.00 sec) 在mysql-slave1和mysql-slave2從資料庫節點檢視 mysql> select * from kevin.haha; +----+-----------+ | id | name | +----+-----------+ | 5 | hefei | | 8 | beijing | | 11 | changping | | 12 | wangjing | | 21 | zhongguo | | 22 | xianggang | | 23 | taiwan | +----+-----------+ 7 rows in set (0.00 sec) 發現在客戶端通過proxysql外掛更新的資料,已經寫到mysql-master主資料庫上,並同步到mysql-slave1和mysql-slave2兩個從資料庫上了! ==========================需要注意======================= 上面測試的客戶機是在mysql-proxy本機,所以用127.0.0.1. 如果是在別的客戶機上,那麼連線命令中就用proxysql的地址,即"mysql -uroot -ppasswd -P6033 -h172.16.60.214" 比如在mysql-slave2機器上連線proxysql外掛: [root@mysql-slave2 ~]# mysql -uroot -ppasswd -P6033 -h172.16.60.214 mysql: [Warning] Using a password on the command line interface can be insecure. Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 47 Server version: 5.5.30 (ProxySQL) Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | kevin | | mysql | | performance_schema | | proxy_test | | sys | +--------------------+ 6 rows in set (0.00 sec) 刪除上面建立的proxy_test測試庫 mysql> drop database proxy_test; Query OK, 1 row affected (0.16 sec) mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | kevin | | mysql | | performance_schema | | sys | +--------------------+ 5 rows in set (0.00 sec) mysql> select * from kevin.haha; +----+-----------+ | id | name | +----+-----------+ | 5 | hefei | | 8 | beijing | | 11 | changping | | 12 | wangjing | | 21 | zhongguo | | 22 | xianggang | | 23 | taiwan | +----+-----------+ 7 rows in set (0.00 sec)
至此,MySQL5.7基於GTID主從複製+並行複製+半同步複製+讀寫分離的環境部署工作已完成。