pxc优点总结：
可以达到时时同步，无延迟现象发生
完全兼容MySQL
对于集群中新节点的加入，维护起来很简单
数据的强一致性
不足之处总结：
只支持Innodb存储引擎
存在多节点update更新问题，也就是写放大问题
在线DDL语句，锁表问题
sst针对新节点加入的传输代价过高的问题
关于写放大的原理图
下面从上次组复制转pxc
https://www.cnblogs.com/omsql/p/9277047.html
pxc架构图如下
卸载mysql
卸载前记得备份my.cnf
yum remove mysql-community-*
安装pxc
yum install http://www.percona.com/downloads/percona-release/redhat/0.1-6/percona-release-0.1-6.noarch.rpm
yum install http://rpmfind.net/linux/dag/redhat/el6/en/x86_64/dag/RPMS/socat-1.7.2.4-1.el6.rf.x86_64.rpm
yum install Percona-XtraDB-Cluster-57
修改my.cnf
#pxc
wsrep_provider=/usr/lib64/galera3/libgalera_smm.so
wsrep_cluster_address=gcomm://192.168.20.201,192.168.20.202,192.168.20.203
wsrep_slave_threads= 8
innodb_autoinc_lock_mode=2
wsrep_node_address=192.168.20.201
wsrep_cluster_name=ht-pxc-cluster
wsrep_node_name=pxc01
pxc_strict_mode=ENFORCING
wsrep_sst_method=xtrabackup-v2
wsrep_sst_auth=sst:ocm123
第一个节点启动
/etc/init.d/mysqld bootstrap-pxc
创建用户
SHOW VARIABLES LIKE 'validate_password%';
set global validate_password_policy=LOW;
set global validate_password_length=4;
create user 'sst'@'localhost' identified by 'ocm123';
grant all privileges on *.* to 'sst'@'localhost' identified by 'ocm123';
flush privileges;
第二个节点启动
/etc/init.d/mysql start
第三个节点启动
/etc/init.d/mysql start
添加第三个节点redis03的时候redis02日志输出如下
1 redis02 2 2018-07-09T15:01:19.004758Z 0 [Note] WSREP: Member 2.0 (pxc03) requested state transfer from '*any*'. Selected 0.0 (pxc02)(SYNCED) as donor. 3 2018-07-09T15:01:19.004800Z 0 [Note] WSREP: Shifting SYNCED -> DONOR/DESYNCED (TO: 7054) 4 2018-07-09T15:01:19.004867Z 5 [Note] WSREP: wsrep_notify_cmd is not defined, skipping notification. 5 2018-07-09T15:01:19.005039Z 0 [Note] WSREP: Initiating SST/IST transfer on DONOR side (wsrep_sst_xtrabackup-v2 --role 'donor' --address '192.168.20.203:4444/xtrabackup_sst//1' --socket '/data/mysql/mysql.sock' --datadir '/data/mysql/' --defaults-file '/etc/my.cnf' --defaults-group-suffix '' --binlog 'mysql-bin' --gtid '62e9006b-8379-11e8-bc64-874d49a77c07:7054') 6 2018-07-09T15:01:19.087469Z 5 [Note] WSREP: DONOR thread signaled with 0
redis02被选为donar，使用xtrabackup备份整个库传到redis03下，同时查看redis03 /data/mysql
[root@redis03 mysql]# ls
galera.cache grastate.dat gvwstate.dat sst_in_progress
恢复完后如下
1 [root@redis03 mysql]# ls 2 auto.cnf grastate.dat ib_logfile1 mysql-bin.000007 public_key.pem server-cert.pem xtrabackup_info 3 ca-key.pem gvwstate.dat ibtmp1 mysql-bin.index pxc server-key.pem xtrabackup_master_key_id 4 ca.pem ht innobackup.move.log mysql.sock redis03-relay-bin-group_replication_applier.000001 sys 5 client-cert.pem ib_buffer_pool innobackup.prepare.log mysql.sock.lock redis03-relay-bin-group_replication_applier.index xb_doublewrite 6 client-key.pem ibdata1 mysql performance_schema redis03-relay-bin-group_replication_recovery.000001 xtrabackup_binlog_pos_innodb 7 galera.cache ib_logfile0 mysql-bin.000006 private_key.pem redis03-relay-bin-group_replication_recovery.index xtrabackup_galera_info
上面输出可以看出sst针对新节点加入的传输代价过高。
查看集群状态
root@redis03> show status like 'wsrep%'; +----------------------------------+-------------------------------------------------------------+ | Variable_name | Value | +----------------------------------+-------------------------------------------------------------+ | wsrep_local_state_uuid | 62e9006b-8379-11e8-bc64-874d49a77c07 | | wsrep_protocol_version | 8 | | wsrep_last_applied | 7054 | | wsrep_last_committed | 7054 | | wsrep_replicated | 0 | | wsrep_replicated_bytes | 0 | | wsrep_repl_keys | 0 | | wsrep_repl_keys_bytes | 0 | | wsrep_repl_data_bytes | 0 | | wsrep_repl_other_bytes | 0 | | wsrep_received | 2 | | wsrep_received_bytes | 285 | | wsrep_local_commits | 0 | | wsrep_local_cert_failures | 0 | | wsrep_local_replays | 0 | | wsrep_local_send_queue | 0 | | wsrep_local_send_queue_max | 1 | | wsrep_local_send_queue_min | 0 | | wsrep_local_send_queue_avg | 0.000000 | | wsrep_local_recv_queue | 0 | | wsrep_local_recv_queue_max | 1 | | wsrep_local_recv_queue_min | 0 | | wsrep_local_recv_queue_avg | 0.000000 | | wsrep_local_cached_downto | 0 | | wsrep_flow_control_paused_ns | 0 | | wsrep_flow_control_paused | 0.000000 | | wsrep_flow_control_sent | 0 | | wsrep_flow_control_recv | 0 | | wsrep_flow_control_interval | [ 173, 173 ] | | wsrep_flow_control_interval_low | 173 | | wsrep_flow_control_interval_high | 173 | | wsrep_flow_control_status | OFF | | wsrep_cert_deps_distance | 0.000000 | | wsrep_apply_oooe | 0.000000 | | wsrep_apply_oool | 0.000000 | | wsrep_apply_window | 0.000000 | | wsrep_commit_oooe | 0.000000 | | wsrep_commit_oool | 0.000000 | | wsrep_commit_window | 0.000000 | | wsrep_local_state | 4 | | wsrep_local_state_comment | Synced | | wsrep_cert_index_size | 0 | | wsrep_cert_bucket_count | 22 | | wsrep_gcache_pool_size | 1320 | | wsrep_causal_reads | 0 | | wsrep_cert_interval | 0.000000 | | wsrep_ist_receive_status | | | wsrep_ist_receive_seqno_start | 0 | | wsrep_ist_receive_seqno_current | 0 | | wsrep_ist_receive_seqno_end | 0 | | wsrep_incoming_addresses | 192.168.20.202:3306,192.168.20.201:3306,192.168.20.203:3306 | | wsrep_desync_count | 0 | | wsrep_evs_delayed | | | wsrep_evs_evict_list | | | wsrep_evs_repl_latency | 0/0/0/0/0 | | wsrep_evs_state | OPERATIONAL | | wsrep_gcomm_uuid | ee9c63ef-8388-11e8-af36-8bf4f2f07974 | | wsrep_cluster_conf_id | 5 | | wsrep_cluster_size | 3 | | wsrep_cluster_state_uuid | 62e9006b-8379-11e8-bc64-874d49a77c07 | | wsrep_cluster_status | Primary | | wsrep_connected | ON | | wsrep_local_bf_aborts | 0 | | wsrep_local_index | 2 | | wsrep_provider_name | Galera | | wsrep_provider_vendor | Codership Oy <info@codership.com> | | wsrep_provider_version | 3.26(rac090bc) | | wsrep_ready | ON | +----------------------------------+-------------------------------------------------------------+
在对pxc做此oltp测试
安装sysbench yum install sysbench 生成数据，创建10个表，每个表百万行 sysbench oltp_common --tables=10 --table-size=1000000 --db-driver=mysql --mysql-db=pxc --mysql-user=root --mysql-password=ocm123 prepare oltp 测试，开启50个并行 sysbench oltp_read_write.lua --db-driver=mysql --mysql-host=127.0.0.1 --mysql-port=3306 --mysql-db=pxc --mysql-user=root --mysql-password=ocm123 --table_size=1000000 --tables=10 --threads=50 --report-interval=10 --time=300 run
oltp测试结果如下
1 [root@redis01 sysbench]# sysbench oltp_read_write.lua --db-driver=mysql --mysql-host=127.0.0.1 --mysql-port=3306 --mysql-db=pxc --mysql-user=root --mysql-password=ocm123 --table_size=1000000 --tables=10 --threads=50 --report-interval=10 --time=300 run 2 sysbench 1.0.14 (using bundled LuaJIT 2.1.0-beta2) 3 4 Running the test with following options: 5 Number of threads: 50 6 Report intermediate results every 10 second(s) 7 Initializing random number generator from current time 8 9 10 Initializing worker threads... 11 12 Threads started! 13 14 [ 10s ] thds: 50 tps: 7.90 qps: 231.92 (r/w/o: 168.04/26.19/37.69) lat (ms,95%): 5813.24 err/s: 0.00 reconn/s: 0.00 15 [ 20s ] thds: 50 tps: 11.80 qps: 254.99 (r/w/o: 177.69/32.30/45.00) lat (ms,95%): 5918.87 err/s: 0.00 reconn/s: 0.00 16 [ 30s ] thds: 50 tps: 8.90 qps: 179.97 (r/w/o: 124.58/26.10/29.30) lat (ms,95%): 6476.48 err/s: 0.00 reconn/s: 0.00 17 [ 40s ] thds: 50 tps: 10.40 qps: 175.17 (r/w/o: 122.35/19.81/33.01) lat (ms,95%): 9284.15 err/s: 0.00 reconn/s: 0.00 18 [ 50s ] thds: 50 tps: 9.20 qps: 182.49 (r/w/o: 131.10/21.90/29.50) lat (ms,95%): 9799.46 err/s: 0.00 reconn/s: 0.00 19 [ 60s ] thds: 50 tps: 8.80 qps: 198.65 (r/w/o: 140.97/24.39/33.29) lat (ms,95%): 7215.39 err/s: 0.00 reconn/s: 0.00 20 [ 70s ] thds: 50 tps: 7.00 qps: 145.72 (r/w/o: 99.01/21.60/25.10) lat (ms,95%): 8795.93 err/s: 0.00 reconn/s: 0.00 21 [ 80s ] thds: 50 tps: 13.70 qps: 239.41 (r/w/o: 171.21/27.20/41.00) lat (ms,95%): 8484.79 err/s: 0.00 reconn/s: 0.00 22 [ 90s ] thds: 50 tps: 7.40 qps: 161.92 (r/w/o: 107.41/24.90/29.60) lat (ms,95%): 8484.79 err/s: 0.00 reconn/s: 0.00 23 [ 100s ] thds: 50 tps: 8.00 qps: 186.69 (r/w/o: 130.99/24.00/31.70) lat (ms,95%): 5918.87 err/s: 0.00 reconn/s: 0.00 24 [ 110s ] thds: 50 tps: 10.00 qps: 200.01 (r/w/o: 140.00/27.40/32.60) lat (ms,95%): 5709.50 err/s: 0.00 reconn/s: 0.00 25 [ 120s ] thds: 50 tps: 10.60 qps: 210.17 (r/w/o: 148.38/25.60/36.19) lat (ms,95%): 8184.67 err/s: 0.00 reconn/s: 0.00 26 [ 130s ] thds: 50 tps: 11.50 qps: 223.73 (r/w/o: 159.42/24.70/39.61) lat (ms,95%): 7895.16 err/s: 0.00 reconn/s: 0.00 27 [ 140s ] thds: 50 tps: 11.90 qps: 242.60 (r/w/o: 168.03/31.09/43.48) lat (ms,95%): 4943.53 err/s: 0.00 reconn/s: 0.00 28 [ 150s ] thds: 50 tps: 9.10 qps: 185.45 (r/w/o: 127.53/26.21/31.71) lat (ms,95%): 4517.90 err/s: 0.00 reconn/s: 0.00 29 [ 160s ] thds: 50 tps: 14.50 qps: 253.44 (r/w/o: 179.83/27.70/45.91) lat (ms,95%): 8184.67 err/s: 0.00 reconn/s: 0.00 30 [ 170s ] thds: 50 tps: 8.40 qps: 203.91 (r/w/o: 140.80/28.10/35.00) lat (ms,95%): 4943.53 err/s: 0.00 reconn/s: 0.00 31 [ 180s ] thds: 50 tps: 13.90 qps: 261.61 (r/w/o: 187.64/28.89/45.08) lat (ms,95%): 7754.26 err/s: 0.00 reconn/s: 0.00 32 [ 190s ] thds: 50 tps: 10.50 qps: 226.94 (r/w/o: 153.93/35.31/37.71) lat (ms,95%): 7754.26 err/s: 0.00 reconn/s: 0.00 33 [ 200s ] thds: 50 tps: 12.00 qps: 218.73 (r/w/o: 153.52/25.30/39.91) lat (ms,95%): 4203.93 err/s: 0.00 reconn/s: 0.00 34 [ 210s ] thds: 50 tps: 11.80 qps: 249.64 (r/w/o: 177.76/29.89/41.99) lat (ms,95%): 5607.61 err/s: 0.00 reconn/s: 0.00 35 [ 220s ] thds: 50 tps: 12.69 qps: 256.80 (r/w/o: 178.93/30.99/46.88) lat (ms,95%): 4517.90 err/s: 0.00 reconn/s: 0.00 36 [ 230s ] thds: 50 tps: 14.01 qps: 253.05 (r/w/o: 180.41/27.62/45.03) lat (ms,95%): 5709.50 err/s: 0.00 reconn/s: 0.00 37 [ 240s ] thds: 50 tps: 9.20 qps: 211.70 (r/w/o: 145.10/31.10/35.50) lat (ms,95%): 5507.54 err/s: 0.00 reconn/s: 0.00 38 [ 250s ] thds: 50 tps: 14.10 qps: 259.32 (r/w/o: 186.52/29.30/43.50) lat (ms,95%): 7086.63 err/s: 0.00 reconn/s: 0.00 39 [ 260s ] thds: 50 tps: 9.20 qps: 210.87 (r/w/o: 139.78/35.00/36.10) lat (ms,95%): 8038.61 err/s: 0.00 reconn/s: 0.00 40 [ 270s ] thds: 50 tps: 11.20 qps: 222.78 (r/w/o: 156.79/27.50/38.50) lat (ms,95%): 6026.41 err/s: 0.00 reconn/s: 0.00 41 [ 280s ] thds: 50 tps: 11.50 qps: 230.55 (r/w/o: 160.73/31.31/38.51) lat (ms,95%): 7615.89 err/s: 0.00 reconn/s: 0.00 42 [ 290s ] thds: 50 tps: 12.80 qps: 255.18 (r/w/o: 179.29/30.90/45.00) lat (ms,95%): 7086.63 err/s: 0.00 reconn/s: 0.00 43 [ 300s ] thds: 50 tps: 12.90 qps: 237.20 (r/w/o: 171.00/24.80/41.40) lat (ms,95%): 6247.39 err/s: 0.00 reconn/s: 0.00 44 SQL statistics: 45 queries performed: 46 read: 46186 47 write: 8348 48 other: 11446 49 total: 65980 50 transactions: 3299 (10.93 per sec.) 51 queries: 65980 (218.52 per sec.) 52 ignored errors: 0 (0.00 per sec.) 53 reconnects: 0 (0.00 per sec.) 54 55 General statistics: 56 total time: 301.9413s 57 total number of events: 3299 58 59 Latency (ms): 60 min: 975.37 61 avg: 4575.91 62 max: 13565.48 63 95th percentile: 7479.98 64 sum: 15095927.24 65 66 Threads fairness: 67 events (avg/stddev): 65.9800/1.97 68 execution time (avg/stddev): 301.9185/0.01
pxc的 qtp才为11 （虚拟机，3节点在一个磁盘上）