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MySQL分區如何遷移

背景

需求來源

MySQL越來越流行,而且存儲在MySQL的資料量也越來越大,單表資料達億行已經是非常常見的現象,而這些表裡面儲存了大量的曆史記錄,嚴重影響SQL執行的效率。本文是針對客戶需求,遷移MySQL Innodb大表分區中部分曆史歸檔分區到其他執行個體或者其他庫表,而且遷移過程盡量減少對業務環境的影響。

環境介紹
  • MySQL 5.7.21
  • Centos 7.4
  • innodb_file_per_table=1

MySQL常用的Innodb遷移方法

  • MySQL Enterprise Backup(實體備份,類似于xtrabackup)
  • Copying Data Files (冷備份)
  • 邏輯導出和導入(mysqldump,mydumper,mysqlpump)
  • 可傳輸的表空間

遷移方案(可傳輸的表空間)

準備工作
  • MySQL版本必須是5.7
  • 遷移過程中存在短暫時間内業務不可寫,建議提前做好準備
操作步驟

檢視需要遷移表(原表)結構

root@localhost : testdba 02:03:18> use test
Database changed

root@localhost : test 08:37:50> show create table sbtest2;
+---------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+---------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| sbtest2 | CREATE TABLE `sbtest2` (
  `id` int(10) DEFAULT NULL,
  `name` varchar(20) COLLATE utf8_bin DEFAULT NULL,
  `date` int(20) DEFAULT NULL,
  KEY `idx_fenqu` (`date`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin
/*!50100 PARTITION BY RANGE (date)
(PARTITION p0 VALUES LESS THAN (20161201) ENGINE = InnoDB,
 PARTITION p1 VALUES LESS THAN (20170101) ENGINE = InnoDB,
 PARTITION p2 VALUES LESS THAN (20170201) ENGINE = InnoDB,
 PARTITION p3 VALUES LESS THAN (20170301) ENGINE = InnoDB,
 PARTITION p4 VALUES LESS THAN (20170401) ENGINE = InnoDB,
 PARTITION p5 VALUES LESS THAN (20170501) ENGINE = InnoDB,
 PARTITION p6 VALUES LESS THAN (20170601) ENGINE = InnoDB,
 PARTITION p7 VALUES LESS THAN (20170701) ENGINE = InnoDB,
 PARTITION p8 VALUES LESS THAN (20170801) ENGINE = InnoDB,
 PARTITION p9 VALUES LESS THAN (20170901) ENGINE = InnoDB,
 PARTITION p10 VALUES LESS THAN (20171001) ENGINE = InnoDB,
 PARTITION p11 VALUES LESS THAN (20171101) ENGINE = InnoDB,
 PARTITION p12 VALUES LESS THAN (20171201) ENGINE = InnoDB,
 PARTITION p13 VALUES LESS THAN (20180101) ENGINE = InnoDB,
 PARTITION p14 VALUES LESS THAN (20180201) ENGINE = InnoDB,
 PARTITION p15 VALUES LESS THAN (20180301) ENGINE = InnoDB,
 PARTITION p16 VALUES LESS THAN (20180401) ENGINE = InnoDB,
 PARTITION p17 VALUES LESS THAN (20180501) ENGINE = InnoDB,
 PARTITION p18 VALUES LESS THAN (20180601) ENGINE = InnoDB,
 PARTITION p19 VALUES LESS THAN MAXVALUE ENGINE = InnoDB) */ |
+---------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)


root@localhost : test 12:04:03> SELECT PARTITION_NAME, TABLE_ROWS FROM INFORMATION_SCHEMA.PARTITIONS WHERE TABLE_NAME = 'sbtest2';
+----------------+------------+
| PARTITION_NAME | TABLE_ROWS |
+----------------+------------+
| p0 | 22 |
| p1 | 2 |
| p2 | 2 |
| p3 | 2 |
| p4 | 2 |
| p5 | 2 |
| p6 | 2 |
| p7 | 2 |
| p8 | 2 |
| p9 | 2 |
| p10 | 2 |
| p11 | 2 |
| p12 | 2 |
| p13 | 2 |
| p14 | 2 |
| p15 | 2 |
| p16 | 2 |
| p17 | 2 |
| p18 | 2 |
| p19 | 14 |
+----------------+------------+
20 rows in set (0.00 sec)           

按照個人遷移分區表需求,可以把曆史分區遷移到其他MySQL執行個體,也可以遷移到同一MySQL執行個體的其他庫中。首先建立與原表相同表結構的分區表,在建立分區表時,我們隻需要建立我們需要遷移的表分區結構。例:下面是遷移案例,由于隻遷移2017年資料,是以表結構隻建立了存儲2017年資料的分區。

root@localhost : test 01:59:36> create database testdba;
Query OK, 1 row affected (0.12 sec)

root@localhost : test 01:59:44> use testdba;
Database changed

root@localhost : testdba 06:04:26> CREATE TABLE `sbtest2` (
    -> id int(10),
    -> name varchar(20),
    -> date int(20),
    -> key idx_fenqu(date)
    -> )
    -> PARTITION BY RANGE (date) (
    -> PARTITION p2 VALUES LESS THAN (20170201),
    -> PARTITION p3 VALUES LESS THAN (20170301),
    -> PARTITION p4 VALUES LESS THAN (20170401),
    -> PARTITION p5 VALUES LESS THAN (20170501),
    -> PARTITION p6 VALUES LESS THAN (20170601),
    -> PARTITION p7 VALUES LESS THAN (20170701),
    -> PARTITION p8 VALUES LESS THAN (20170801),
    -> PARTITION p9 VALUES LESS THAN (20170901),
    -> PARTITION p10 VALUES LESS THAN (20171001),
    -> PARTITION p11 VALUES LESS THAN (20171101),
    -> PARTITION p12 VALUES LESS THAN (20171201),
    -> PARTITION p13 VALUES LESS THAN (20180101)
    -> );
Query OK, 0 rows affected (0.22 sec)           

清除新表所有的分區獨立表空間,為導入原表的分區獨立表空間做準備

root@localhost : testdba 02:00:05> use testdba;
Database changed

root@localhost : testdba 02:00:23> ALTER TABLE sbtest2 DISCARD PARTITION p2,p3,p4,p5,p6,p7,p8,p9,p10,p11,p12,p13 TABLESPACE;
Query OK, 0 rows affected (0.27 sec)           

在原表中執行FLUSH TABLES ... FOR EXPORT(在分區表空間傳輸沒有完成之前,不要退出該會話或者執行unlock tables;操作),用來擷取中繼資料校驗檔案.cfg和確定該表的髒頁刷到磁盤,并加共享表鎖

root@localhost : testdba 02:00:24> USE test;
Database changed

root@localhost : test 02:00:29> FLUSH TABLES test.sbtest2 FOR EXPORT;
Query OK, 0 rows affected (0.00 sec)

[root@slave test]# cd /var/lib/mysql/data/mydata/test

[root@slave test]# ls 
db.opt sbtest2#P#p10.cfg sbtest2#P#p12.ibd sbtest2#P#p15.cfg sbtest2#P#p17.ibd sbtest2#P#p2.cfg sbtest2#P#p4.ibd sbtest2#P#p7.cfg sbtest2#P#p9.ibd
sbtest2#P#p0.cfg sbtest2#P#p10.ibd sbtest2#P#p13.cfg sbtest2#P#p15.ibd sbtest2#P#p18.cfg sbtest2#P#p2.ibd sbtest2#P#p5.cfg sbtest2#P#p7.ibd sbtest2.frm
sbtest2#P#p0.ibd sbtest2#P#p11.cfg sbtest2#P#p13.ibd sbtest2#P#p16.cfg sbtest2#P#p18.ibd sbtest2#P#p3.cfg sbtest2#P#p5.ibd sbtest2#P#p8.cfg
sbtest2#P#p1.cfg sbtest2#P#p11.ibd sbtest2#P#p14.cfg sbtest2#P#p16.ibd sbtest2#P#p19.cfg sbtest2#P#p3.ibd sbtest2#P#p6.cfg sbtest2#P#p8.ibd
sbtest2#P#p1.ibd sbtest2#P#p12.cfg sbtest2#P#p14.ibd sbtest2#P#p17.cfg sbtest2#P#p19.ibd sbtest2#P#p4.cfg sbtest2#P#p6.ibd sbtest2#P#p9.cfg           

進入到原表ibd所在的目錄下,把原表需要遷移的分區表空間和中繼資料校驗檔案.cfg傳輸到新表所在的位置,并賦予權限

[root@slave test]# cp sbtest2#P#p2.* sbtest2#P#p3.* sbtest2#P#p4.* sbtest2#P#p5.* sbtest2#P#p6.* sbtest2#P#p7.* sbtest2#P#p8.* sbtest2#P#p9.* sbtest2#P#p10.* sbtest2#P#p11.* sbtest2#P#p12.* sbtest2#P#p13.* /var/lib/mysql/data/mydata/testdba/

[root@slave test]# ls ../testdba/
db.opt sbtest2#P#p11.cfg sbtest2#P#p12.ibd sbtest2#P#p2.cfg sbtest2#P#p3.ibd sbtest2#P#p5.cfg sbtest2#P#p6.ibd sbtest2#P#p8.cfg sbtest2#P#p9.ibd
sbtest2#P#p10.cfg sbtest2#P#p11.ibd sbtest2#P#p13.cfg sbtest2#P#p2.ibd sbtest2#P#p4.cfg sbtest2#P#p5.ibd sbtest2#P#p7.cfg sbtest2#P#p8.ibd sbtest2.frm
sbtest2#P#p10.ibd sbtest2#P#p12.cfg sbtest2#P#p13.ibd sbtest2#P#p3.cfg sbtest2#P#p4.ibd sbtest2#P#p6.cfg sbtest2#P#p7.ibd sbtest2#P#p9.cfg

[root@slave test]# chown -R mysql:mysql /var/lib/mysql           

切回到執行FLUSH TABLES ... FOR EXPORT語句視窗,釋放共享表鎖

root@localhost : test 02:00:29> USE test;
Database changed

root@localhost : test 02:01:07> UNLOCK TABLES;
Query OK, 0 rows affected (0.00 sec)           

進入新表所在的執行個體或新表所在的庫,手動導入分區表空間,進行資料恢複(應用傳輸到新表的分區表空間)

root@localhost : test 02:01:07> USE testdba;
Database changed

root@localhost : testdba 02:01:14> ALTER TABLE sbtest2 IMPORT PARTITION p2,p3,p4,p5,p6,p7,p8,p9,p10,p11,p12,p13 TABLESPACE;
Query OK, 0 rows affected (0.62 sec)           

表空間遷移完成,資料恢複完成,最後校驗資料準确性

root@localhost : testdba 02:03:16> SELECT PARTITION_NAME, TABLE_ROWS FROM INFORMATION_SCHEMA.PARTITIONS WHERE TABLE_NAME = 'sbtest2' and TABLE_SCHEMA='testdba';
+----------------+------------+
| PARTITION_NAME | TABLE_ROWS |
+----------------+------------+
| p2 | 2 |
| p3 | 2 |
| p4 | 2 |
| p5 | 2 |
| p6 | 2 |
| p7 | 2 |
| p8 | 2 |
| p9 | 2 |
| p10 | 2 |
| p11 | 2 |
| p12 | 2 |
| p13 | 2 |
+----------------+------------+
12 rows in set (0.00 sec)           

總結

  • 以上是我們使用MySQL的分區表空間傳輸方法,解決了分區表曆史資料歸檔到其他執行個體或者同一執行個體其他庫的問題。對比邏輯遷移方式mysqldump或者insert .. select ...方式速度更快,資料立即可用,而且對業務的影響更小。

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