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分布式 | 利用 TiDB DM 将数据从 MySQL 迁移至 DBLE
作者：沈光宇
爱可生南区 DBA 团队成员，主要负责 MySQL 故障处理和性能优化。对技术执着，为客户负责。
本文来源：原创投稿
*爱可生开源社区出品，原创内容未经授权不得随意使用，转载请联系小编并注明来源。
一、背景
某客户MySQL实例中数据较大(上T的数据量)，需要将MySQL中数据全量/增量快速迁移至DBLE。TiDB DM支持多线程数据导出导入及增量同步，因此选择了TiDB DM为作数据迁移工具。本文以此案例为背景，介绍使用TiDB DM将数据从MySQL迁移至DBLE的方法及遇到的一些问题。
二、数据迁移示意图及服务器环境
（1）数据迁移示意图如下：
（2）服务器环境如下:
服务器IP 角色 端口 版本 备注 10.186.65.83 dm master 8261/8291 V2.0.7 tiup安装节点 10.186.65.118 dm worker 8262 V2.0.7 10.186.65.14 SRC MySQL 4490 MySQL 8.0.18 10.186.65.4 DBLE 8066 DBLE 3.21.10.6 10.186.65.61 DBLE datanode 4408 MySQL 8.0.25 10.186.65.65 DBLE datanode 4408 MySQL 8.0.25 三、安装 TiDB DM
（1）准备环境及安装 tiup
#分别在dm master和worker节点主机创建tidb用户,密码为dmadmin,并配置sudo shell> useradd tidb shell> echo "dmadmin" | passwd tidb --stdin shell> echo "tidb ALL=(ALL) NOPASSWD: ALL" > /etc/sudoers.d/tidb #切换至tidb用户,生成密钥，并做ssh信任,dm集群内机器都需要做ssh信任 shell> su - tidb shell> ssh-keygen -t rsa shell> ssh-copy-id -i ~/.ssh/id_rsa.pub tidb@10.186.65.118 shell> ssh-copy-id -i ~/.ssh/id_rsa.pub tidb@10.186.65.83 #安装tiup,在tidb用户下 shell> curl --proto '=https' --tlsv1.2 -sSf https://tiup-mirrors.pingcap.com/install.sh | sh shell> source .bash_profile shell> which tiup ~/.tiup/bin/tiup #安装dmctl shell> tiup install dm dmctl:v2.0.7 component dm version v1.10.2 is already installed download https://tiup-mirrors.pingcap.com/dmctl-v2.0.7-linux-amd64.tar.gz 26.92 MiB / 26.92 MiB 100.00% 10.01 MiB/s- 1
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（2）安装dm-cluster
#生成配置模版 shell> tiup dm template > dm_topology.yaml #修改后配置文件如下： shell> cat dm_topology.yaml |grep -v ^[#-] |grep -v ^$ global: user: "tidb" ssh_port: 22 deploy_dir: "/home/tidb/dm/deploy" data_dir: "/home/tidb/dm/data" master_servers: - host: 10.186.65.83 worker_servers: - host: 10.186.65.118 monitoring_servers: - host: 10.186.65.83 grafana_servers: - host: 10.186.65.83 alertmanager_servers: - host: 10.186.65.83 #安装、并启动DM集群 shell> tiup dm deploy dm-test v2.0.7 ./dm_topology.yaml --user tidb -i /home/tidb/.ssh/id_rsa shell> tiup dm start dm-test #查看DM集群 [tidb@10_186_65_83 ~]$ tiup dm display dm-test tiup is checking updates for component dm ... Starting component `dm`: /home/tidb/.tiup/components/dm/v1.10.2/tiup-dm display dm-test Cluster type: dm Cluster name: dm-test Cluster version: v2.0.7 Deploy user: tidb SSH type: builtin Grafana URL: http://10.186.65.83:3000 ID Role Host Ports OS/Arch Status Data Dir Deploy Dir -- ---- ---- ----- ------- ------ -------- ---------- 10.186.65.83:9093 alertmanager 10.186.65.83 9093/9094 linux/x86_64 Up /home/tidb/dm/data/alertmanager-9093 /home/tidb/dm/deploy/alertmanager-9093 10.186.65.83:8261 dm-master 10.186.65.83 8261/8291 linux/x86_64 Healthy|L /home/tidb/dm/data/dm-master-8261 /home/tidb/dm/deploy/dm-master-8261 10.186.65.118:8262 dm-worker 10.186.65.118 8262 linux/x86_64 Free /home/tidb/dm/data/dm-worker-8262 /home/tidb/dm/deploy/dm-worker-8262 10.186.65.83:3000 grafana 10.186.65.83 3000 linux/x86_64 Up - /home/tidb/dm/deploy/grafana-3000 10.186.65.83:9090 prometheus 10.186.65.83 9090 linux/x86_64 Up /home/tidb/dm/data/prometheus-9090 /home/tidb/dm/deploy/prometheus-9090 Total nodes: 5- 1
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四、DBLE端配置
（1）db.xml
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（2）sharding.xml
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（3）user.xml
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（4）登陆 DBLE 管理端执行创建物理数据库命令
shell> /data/mysql/base/5.7.36/bin/mysql -uroot -padmin -h 10.186.65.4 -P 9066 dble> create database @@shardingNode = 'dn$1-4'; Query OK, 1 row affected (0.06 sec) dble> create database @@shardingNode = 'dm_meta'; Query OK, 1 row affected (0.01 sec)- 1
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五、在源端 MySQL 压测创建测试数据
#执行prepare，初始化100W行数据 /usr/share/sysbench/oltp_insert.lua --mysql-db=sbtest --mysql-host=10.186.65.14 --mysql-port=4490 --mysql-user=sgy --mysql-password=admin --tables=2 --table-size=1000000 --threads=16 --time=60 --report-interval=1 --max-requests=0 --percentile=95 --mysql-ignore-errors=1062 prepare sysbench 1.0.17 (using system LuaJIT 2.0.4) Initializing worker threads... Creating table 'sbtest1'... Creating table 'sbtest2'... Inserting 1000000 records into 'sbtest2' Inserting 1000000 records into 'sbtest1' Creating a secondary index on 'sbtest2'... Creating a secondary index on 'sbtest1'... #利用sysbench不断写入数据 shell> /usr/share/sysbench/oltp_read_write.lua --mysql-db=sbtest --mysql-host=10.186.65.14 --mysql-port=4490 --mysql-user=sgy --mysql-password=admin --tables=2 --table-size=2000000 --threads=16 --time=6000 --report-interval=1 --max-requests=0 --percentile=95 --mysql-ignore-errors=1062 run sysbench 1.0.17 (using system LuaJIT 2.0.4) Running the test with following options: Number of threads: 16 Report intermediate results every 1 second(s) Initializing random number generator from current time Initializing worker threads... Threads started! [ 1s ] thds: 16 tps: 585.44 qps: 11916.49 (r/w/o: 8360.33/1282.63/2273.53) lat (ms,95%): 55.82 err/s: 0.00 reconn/s: 0.00 [ 2s ] thds: 16 tps: 744.18 qps: 14819.02 (r/w/o: 10379.16/1609.36/2830.50) lat (ms,95%): 41.85 err/s: 0.00 reconn/s: 0.00 [ 3s ] thds: 16 tps: 605.11 qps: 12144.20 (r/w/o: 8500.54/1321.24/2322.42) lat (ms,95%): 47.47 err/s: 0.00 reconn/s: 0.00 [ 4s ] thds: 16 tps: 773.91 qps: 15558.16 (r/w/o: 10881.71/1737.79/2938.65) lat (ms,95%): 41.10 err/s: 0.00 reconn/s: 0.00- 1
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六、启动数据同步任务
（1）配置数据源
#使用dmctl工具生成密码加密字符串,每次执行都会产生不同的加密字符串 shell> tiup dmctl encrypt 'admin' dmXgktpuF18RP1mDN/B2UkA6pDN9PQ== #mysql数据库配置文件如下 shell> cat mysql_source_14_4490.yaml source-id: "mysql_source_14_4490" from: host: "10.186.65.14" port: 4490 user: "sgy" password: "dmXgktpuF18RP1mDN/B2UkA6pDN9PQ==" #创建数据源 shell> tiup dmctl --master-addr 10.186.65.83:8261 operate-source create ./mysql_source_14_4490.yaml Starting component `dmctl`: /home/tidb/.tiup/components/dmctl/v2.0.7/dmctl/dmctl --master-addr 10.186.65.83:8261 operate-source create ./mysql_source_14_4490.yaml { "result": true, "msg": "", "sources": [ { "result": true, "msg": "", "source": "mysql_source_14_4490", "worker": "dm-10.186.65.118-8262" } ] } #查看数据源 shell> tiup dmctl --master-addr 10.186.65.83:8261 operate-source show { "result": true, "msg": "", "sources": [ { "result": true, "msg": "", "source": "mysql_source_14_4490", "worker": "dm-10.186.65.118-8262" } ] }- 1
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（2）配置同步任务
#同步配置文件如下 shell> cat mysql_sync_to_dble.yaml name: "mysql_sync_to_dble" #同步任务名 task-mode: "all" #全量 + Binlog 实时同步 clean-dump-file: true timezone: "Asia/Shanghai" ignore-checking-items: ["auto_increment_ID"] target-database: host: "10.186.65.4" #DBLE主机IP地址 port: 8066 #DBLE流量端口 user: "sz" #连接DBLE的用户 password: "KRfSNtdxe63tehpnCYoCz0ABdUGivg==" #连接DBLE用户密码，用tiup dmctl encrypt 'password'生成 mysql-instances: - source-id: "mysql_source_14_4490" block-allow-list: "global" mydumper-config-name: "global" loader-config-name: "global" syncer-config-name: "global" block-allow-list: global: do-dbs: ["sbtest"] #只迁移sbtest库 mydumpers: global: extra-args: "-B sbtest" #只dump sbtest库 loaders: global: pool-size: 8 syncers: global: worker-count: 8 #更详细配置说明参考官方文档： https://docs.pingcap.com/zh/tidb-data-migration/v2.0/task-configuration-file-full#%E5%AE%8C%E6%95%B4%E9%85%8D%E7%BD%AE%E6%96%87%E4%BB%B6%E7%A4%BA%E4%BE%8B #检查配置文件 shell> tiup dmctl:v2.0.7 --master-addr=10.186.65.83:8261 check-task ./mysql_sync_to_dble.yaml Starting component `dmctl`: /home/tidb/.tiup/components/dmctl/v2.0.7/dmctl/dmctl --master-addr=10.186.65.83:8261 check-task ./mysql_sync_to_dble.yaml { "result": true, "msg": "check pass!!!" } #启动同步任务 shell> tiup dmctl:v2.0.7 --master-addr=10.186.65.83:8261 start-task ./mysql_sync_to_dble.yaml Starting component `dmctl`: /home/tidb/.tiup/components/dmctl/v2.0.7/dmctl/dmctl --master-addr=10.186.65.83:8261 start-task ./mysql_sync_to_dble.yaml { "result": true, "msg": "", "sources": [ { "result": true, "msg": "", "source": "mysql_source_14_4490", "worker": "dm-10.186.65.118-8262" } ] } #在dm-worker节点查看导出的SQL文件, shell> ls -lh /home/tidb/dm/deploy/dm-worker-8262/dumped_data.mysql_sync_to_dble total 384M -rw-r--r-- 1 tidb tidb 187 Aug 5 14:04 metadata -rw-r--r-- 1 tidb tidb 48M Aug 5 14:04 sbtest.sbtest1.0000000000000.sql -rw-r--r-- 1 tidb tidb 48M Aug 5 14:04 sbtest.sbtest1.0000000010000.sql -rw-r--r-- 1 tidb tidb 48M Aug 5 14:04 sbtest.sbtest1.0000000020000.sql -rw-r--r-- 1 tidb tidb 48M Aug 5 14:04 sbtest.sbtest1.0000000030000.sql -rw-r--r-- 1 tidb tidb 369 Aug 5 14:04 sbtest.sbtest1-schema.sql -rw-r--r-- 1 tidb tidb 48M Aug 5 14:04 sbtest.sbtest2.0000000000000.sql -rw-r--r-- 1 tidb tidb 48M Aug 5 14:04 sbtest.sbtest2.0000000010000.sql -rw-r--r-- 1 tidb tidb 48M Aug 5 14:04 sbtest.sbtest2.0000000020000.sql -rw-r--r-- 1 tidb tidb 48M Aug 5 14:04 sbtest.sbtest2.0000000030000.sql -rw-r--r-- 1 tidb tidb 369 Aug 5 14:04 sbtest.sbtest2-schema.sql -rw-r--r-- 1 tidb tidb 152 Aug 5 14:04 sbtest-schema-create.sql #创建库SQL文件 shell> head /home/tidb/dm/deploy/dm-worker-8262/dumped_data.mysql_sync_to_dble/sbtest-schema-create.sql /*!40101 SET NAMES binary*/; CREATE DATABASE `sbtest` /*!40100 DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_bin */ /*!80016 DEFAULT ENCRYPTION='N' */; #创建表SQL文件 shell> head /home/tidb/dm/deploy/dm-worker-8262/dumped_data.mysql_sync_to_dble/sbtest.sbtest1-schema.sql /*!40101 SET NAMES binary*/; CREATE TABLE `sbtest1` ( `id` int(11) NOT NULL AUTO_INCREMENT, `k` int(11) NOT NULL DEFAULT '0', `c` char(120) COLLATE utf8mb4_bin NOT NULL DEFAULT '', `pad` char(60) COLLATE utf8mb4_bin NOT NULL DEFAULT '', PRIMARY KEY (`id`), KEY `k_1` (`k`) ) ENGINE=InnoDB AUTO_INCREMENT=1000001 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin; #dump生成批量插入数据SQL文件 shell> head /home/tidb/dm/deploy/dm-worker-8262/dumped_data.mysql_sync_to_dble/sbtest.sbtest1.0000000000000.sql /*!40101 SET NAMES binary*/; INSERT INTO `sbtest1` (`id`,`k`,`c`,`pad`) VALUES (1,498670,'31451373586-15688153734-79729593694-96509299839-83724898275-86711833539-78981337422-35049690573-51724173961-87474696253','98996621624-36689827414-04092488557-09587706818-65008859162'), (2,497778,'21472970079-70972780322-70018558993-71769650003-09270326047-32417012031-10768856803-14235120402-93989080412-18690312264','04776826683-45880822084-77922711547-29057964468-76514263618'), (3,498956,'49376827441-24903985029-56844662308-79012577859-40518387141-60588419212-24399130405-42612257832-29494881732-71506024440','26843035807-96849339132-53943793991-69741192222-48634174017'), (4,518727,'85762858421-36258200885-10758669419-44272723583-12529521893-95630803635-53907705724-07005352902-43001596772-53048338959','37979424284-37912826784-31868864947-42903702727-96097885121'), (5,502480,'24805466175-85245528617-94635882649-46305216925-28637832581-03224489581-68883711727-95491561683-91969681472-12022277774','19288959552-55556468076-14192290426-55457672510-18043372364'), (6,500774,'52892836230-54177743992-01821871718-48412537487-30066596248-87215430797-00375777469-64498831720-58542556455-90784765418','59487960480-08453890592-99628797439-16757639138-29377916560'), (7,501466,'85820931248-14475640036-11980694501-86588543167-31029306229-09626867980-90685354565-02350460358-25863585366-53793794448','26081374730-86321700986-51212137094-30635959762-03880194434'), (8,497838,'81578049255-33453976301-67096870761-27658738403-30546242249-53677469854-26594573136-34292002037-52736825353-99165193170','64289062455-51067794311-09919261228-11533354367-07401173317'),- 1
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（3）查看同步任务状态
shell> tiup dmctl:v2.0.7 --master-addr=10.186.65.83:8261 query-status ./mysql_sync_to_dble.yaml Starting component `dmctl`: /home/tidb/.tiup/components/dmctl/v2.0.7/dmctl/dmctl --master-addr=10.186.65.83:8261 query-status ./mysql_sync_to_dble.yaml { "result": true, "msg": "", "sources": [ { "result": true, "msg": "", "sourceStatus": { "source": "mysql_source_14_4490", "worker": "dm-10.186.65.118-8262", "result": null, "relayStatus": null }, "subTaskStatus": [ { "name": "mysql_sync_to_dble", "stage": "Running", "unit": "Sync", "result": null, "unresolvedDDLLockID": "", "sync": { "totalEvents": "425355", "totalTps": "1203", "recentTps": "2386", "masterBinlog": "(mysql-bin.000027, 76114275)", "masterBinlogGtid": "c7827165-bf89-11ec-92e6-02000aba410e:1-5091258", "syncerBinlog": "(mysql-bin.000026, 229462770)", "syncerBinlogGtid": "", "blockingDDLs": [ ], "unresolvedGroups": [ ], "synced": false, "binlogType": "remote", "secondsBehindMaster": "38" } } ] } ] }- 1
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七、验证数据
#暂停先前执行的sysbench程序，确保dm同步与源端无延迟时，对表作count(*) #在源端MySQL，对表进行count(*) mysql> select count(*) from sbtest.sbtest1; +----------+ | count(*) | +----------+ | 1116471 | +----------+ 1 row in set (0.68 sec) mysql> select count(*) from sbtest.sbtest2; +----------+ | count(*) | +----------+ | 1117020 | +----------+ 1 row in set (0.54 sec) #通过dble对表进行count(*) dble> select count(*) from sbtest.sbtest1; +----------+ | count(*) | +----------+ | 1116471 | +----------+ 1 row in set (1.04 sec) dble> select count(*) from sbtest.sbtest2; +----------+ | count(*) | +----------+ | 1117020 | +----------+ 1 row in set (1.58 sec) #在源端数据进行更新操作 mysql> update sbtest.sbtest1 set c=uuid() where id=20; Query OK, 1 row affected (0.01 sec) Rows matched: 1 Changed: 1 Warnings: 0 mysql> select * from sbtest.sbtest1 where id=20; +----+--------+--------------------------------------+-------------------------------------------------------------+ | id | k | c | pad | +----+--------+--------------------------------------+-------------------------------------------------------------+ | 20 | 501448 | 24649f0f-14d1-11ed-b4f2-02000aba410e | 91052688950-96415657187-00012408429-12357288330-41295735957 | +----+--------+--------------------------------------+-------------------------------------------------------------+ 1 row in set (0.00 sec) #通过dble查询数据 dble> select * from sbtest.sbtest1 where id=20; +----+--------+--------------------------------------+-------------------------------------------------------------+ | id | k | c | pad | +----+--------+--------------------------------------+-------------------------------------------------------------+ | 20 | 501448 | 24649f0f-14d1-11ed-b4f2-02000aba410e | 91052688950-96415657187-00012408429-12357288330-41295735957 | +----+--------+--------------------------------------+-------------------------------------------------------------+ 1 row in set (0.01 sec)- 1
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八、注意事项
（1）TiDB DM版本要求：TiDB DM v2.0.7
（2）在进行数据量导入时需要关闭DBLE慢查询日志
#由于数据同步在全量导入阶段会产生大量慢查询，需要在执行同步任务之前先关闭DBLE的慢查询日志 shell> mysql --prompt='dble>' -uroot -p -h 10.186.65.4 -P 9066 #查看慢查询日志状态，1表示开启，0表示关闭 dble> show @@slow_query_log; +------------------+ | @@slow_query_log | +------------------+ | 1 | +------------------+ 1 row in set (0.00 sec) #全量数据导入前，关闭dble慢查询日志 dble> disable @@slow_query_log; Query OK, 1 row affected (0.01 sec) disable slow_query_log success #待全量数据导入完成后，开启dble慢查询日志 dble> enable @@slow_query_log; Query OK, 1 row affected (0.01 sec) enable slow_query_log success- 1
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（3）检查源端 MySQL 实例上是否有运行类似 pt-kill 的程序
#如果在源端MySQL实例上运行有pt-kill或类似的程序，DM同步任务在执行全量数据dump阶段， 导出线程可能会被程序kill掉，导致全备失败。dm-worker.log日志如下： [ERROR] [subtask.go:311] ["unit process error"] [subtask=oms-sync-receiver] [unit=Dump] ["error information"="{\"ErrCode\":32001,\"ErrClass\":\"dump-unit\",\"ErrScope\":\"internal\",\"ErrLevel\":\"high\",\"Message\":\"mydumper/dumpling runs with error, with output (may empty): \",\"RawCause\":\"invalid connection\"}"] 解决方法：先将pt-kill实用工具停止，然后再重新运行TiDM同步任务，待全量数据dump完成后在开启pt-kill。- 1
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（4）迁移时如需对目标表表结构进行修改，如源表有建立分区而目标表通过分片后不需要建立分区、修改表字符集(建议使用utf8mb4)等，可先将表结构从源库导出，修改后导入 DBLE 或导入 DBLE 后在修改表结构，最后再开启 DM 同步任务。
（5）源、目标表字段顺序必须要一致，否则可能会导致数据不一致，两字段同为 varchar 并且长度不相等时，同步任务并不会报错，但写入目标表的值可能会被截断，如下图：
DM 任务启动后连接目标端时，会将 session 级别 sql_mode 设置成下面值：
sql_mode=‘IGNORE_SPACE,NO_AUTO_VALUE_ON_ZERO,NO_ENGINE_SUBSTITUTION,ALLOW_INVALID_DATES,ONLY_FULL_GROUP_BY’； -
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- 原文地址：https://blog.csdn.net/ActionTech/article/details/126364260
