• MySQL没有备份怎么恢复被drop的表(利用undrop-for-innodb)


    介绍:

        也许大家都难以理解,这么重要的数据为啥不备份(或者备份不可用)?而且还任性的drop table了。显然有备份是最好的,但是它们并不总是可用的。这种情况令人恐惧,但并非毫无希望。在许多情况下,可以恢复数据库或表中的几乎所有数据。恢复计划取决于InnoDB是否将所有数据保存在一个ibdata1中,还是每个表都有自己的表空间。本文将考虑innodb_file_per_table=OFF的情况。

    drop 表恢复其他方法:

    本文重要部分:

    环境:

    • 时间:#Sat Aug 4 19:37:24 CST 2018
    • CentOS Linux release 7.2.1511 (Core)
    • MySQL:5.7.23-log
    • 使用工具:undrop-for-innodb

    1.工具安装

    • 依赖包安装
    yum install -y make gcc flex bison
    • 下载工具包(github)
    #cd /opt/
    [root@db13_19:55:25 /opt]  
    #git clone https://github.com/twindb/undrop-for-innodb.git
    Cloning into 'undrop-for-innodb'...
    Resolving deltas: 100% (77/77), done.
    • make
    #cd /opt/undrop-for-innodb
    #make
    ....
    
    ....
    [root@db13_20:39:43 /opt/undrop-for-innodb]  
    #ll
    total 2920
    -rw-r--r-- 1 root root    6271 Aug  4 19:55 check_data.c
    -rw-r--r-- 1 root root   66128 Aug  4 20:39 check_data.o
    -rwxr-xr-x 1 root root  727801 Aug  4 20:39 c_parser
    -rw-r--r-- 1 root root   28587 Aug  4 19:55 c_parser.c
    -rw-r--r-- 1 root root 1030296 Aug  4 20:39 c_parser.o
    drwxr-xr-x 2 root root      92 Aug  4 19:55 dictionary
    -rw-r--r-- 1 root root    1978 Aug  4 19:55 fetch_data.sh
    drwxr-xr-x 2 root root    4096 Aug  4 19:55 include
    -rw-r--r-- 1 root root    8936 Aug  4 19:55 innochecksum.c
    -rwxr-xr-x 1 root root   36343 Aug  4 20:39 innochecksum_changer
    -rw-r--r-- 1 root root  154459 Aug  4 20:39 lex.yy.c
    -rw-r--r-- 1 root root   18047 Aug  4 19:55 LICENSE
    -rw-r--r-- 1 root root    1942 Aug  4 19:55 Makefile
    -rw-r--r-- 1 root root   16585 Aug  4 19:55 print_data.c
    -rw-r--r-- 1 root root  127176 Aug  4 20:39 print_data.o
    -rw-r--r-- 1 root root    3464 Aug  4 19:55 README.md
    -rwxr-xr-x 1 root root    1536 Aug  4 19:55 recover_dictionary.sh
    drwxr-xr-x 2 root root    4096 Aug  4 19:55 sakila
    -rw-r--r-- 1 root root  103506 Aug  4 20:39 sql_parser.c
    -rw-r--r-- 1 root root    8462 Aug  4 19:55 sql_parser.l
    -rw-r--r-- 1 root root  296840 Aug  4 20:39 sql_parser.o
    -rw-r--r-- 1 root root   26355 Aug  4 19:55 sql_parser.y
    -rwxr-xr-x 1 root root   61725 Aug  4 20:39 stream_parser
    -rw-r--r-- 1 root root   23103 Aug  4 19:55 stream_parser.c
    -rw-r--r-- 1 root root  109304 Aug  4 20:39 stream_parser.o
    -rw-r--r-- 1 root root   14764 Aug  4 19:55 sys_parser.c
    -rw-r--r-- 1 root root    2182 Aug  4 19:55 tables_dict.c
    -rw-r--r-- 1 root root   40264 Aug  4 20:39 tables_dict.o
    -rwxr-xr-x 1 root root    6629 Aug  4 19:55 test.sh
    drwxr-xr-x 3 root root      42 Aug  4 19:55 vagrant
    [root@db13_20:39:57 /opt/undrop-for-innodb]  

    • 增加用于恢复表结构的工具sys_parser(官方文档未使用):
    #gcc `/usr/local/mysql57/bin/mysql_config --cflags` `/usr/local/mysql57/bin/mysql_config --libs` -o sys_parser sys_parser.c
     注:mysql_basedir: /usr/local/mysql57/bin/ 

    2.表数据生成和drop表

    • 初始化一个新实例:
    [root@db212_20:58:44 /data/57mysql]  
    #mkdir mysql3507/{data,logs,tmp} -p
    #chown -R mysql:mysql mysql3507
    [root@db212_21:07:34 /3507]  
    \复制my3507.cnf到mysql3507下
    #ln -s /data/57mysql/mysql3507/ /3507
    #/usr/local/mysql57/bin/mysqld --defaults-file=/3507/my3507.cnf --initialize-insecure
    #/usr/local/mysql57/bin/mysqld --defaults-file=/3507/my3507.cnf&
    [1] 11669
    //取初始密码并登录:
    /usr/local/mysql57/bin/mysql -S /tmp/mysql3507.sock -uroot 
    (unknown)@localhost [(none)]>alter user user() identified by '*****';
    root@localhost [(none)]>CREATE DATABASE wenyz;
    root@localhost [(none)]>use wenyz;
    Database changed
    //创建表
    root@localhost [wenyz]>CREATE TABLE `t2` (
        ->   `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
        ->   `ti` varchar(100) NOT NULL,
        ->   `date` date DEFAULT NULL,
        ->   PRIMARY KEY (`id`)
        -> ) ENGINE=InnoDB AUTO_INCREMENT=4079859 DEFAULT CHARSET=utf8;
    Query OK, 0 rows affected (0.01 sec)
    //造数据
    root@localhost [wenyz]>insert into t2(ti,date) values(substring(MD5(RAND()),floor(RAND()*26)+1,15),now()) ;
    Records: 448  Duplicates: 0  Warnings: 0
    
    //查看数据行数和checksum值
    root@localhost [wenyz]>select count(*) from t2;
    +----------+
    | count(*) |
    +----------+
    |      896 |
    +----------+
    root@localhost [wenyz]>checksum table t2;
    +----------+------------+
    | Table    | Checksum   |
    +----------+------------+
    | wenyz.t2 | 3458542072 |
    +----------+------------+
    
    //DROP 表
    root@localhost [wenyz]>drop table t2;
    Query OK, 0 rows affected (0.01 sec)
    

    3.利用stream_parser将ibdata1文件导出成page文件

    #cd /opt/undrop-for-innodb/
    [root@db212_21:25:52 /opt/undrop-for-innodb]  
    #./stream_parser -f /3507/data/ibdata1
    Opening file: /3507/data/ibdata1
    File information:
    ....
    Size to process:                 104857600 (100.000 MiB)
    Size to process:                 104857600 (100.000 MiB)
    time of last access:            1533388916 Sat Aug  4 21:21:56 2018
    time of last modification:      1533388917 Sat Aug  4 21:21:57 2018
    time of last status change:     1533388917 Sat Aug  4 21:21:57 2018
    total size, in bytes:            104857600 (100.000 MiB)
    
    Size to process:                 104857600 (100.000 MiB)
    All workers finished in 0 sec

    4.恢复表结构 [ Top ]

    这里引入官方的一段描述:

    InnoDB stores all data in B+tree indexes. A table has one clustered index PRIMARY, all fields are stored there. Thus, if the table has secondary keys, each key has an index. Each index is identified by index_id.

    Consequently, if we want to recover a table, we have to find all pages that belong to a particular index_id.

    • 接下来我们先来看看怎么找到table id和INDEX_ID(page文件编号)的,理解原理后再用程序跑一次,导入到临时数据库中

    • 手工查找table id
      观察以下结果中,wenyz/t2后的40,即为table id
    [root@db212_21:25:55 /opt/undrop-for-innodb]  
    #./c_parser -4Df pages-ibdata1/FIL_PAGE_INDEX/0000000000000001.page -t dictionary/SYS_TABLES.sql | grep 'wenyz/t2' 
    000000000521    3B00000149047E  SYS_TABLES  "wenyz/t2"  40  3   33  0   64  ""  0
    SET FOREIGN_KEY_CHECKS=0;
    LOAD DATA LOCAL INFILE '000000000521    3B00000149047E  SYS_TABLES  "wenyz/t2"  40  3   33  0   64  ""  0
    
    • 通过table id查看page文件编号
      观察以下结果中40后的41,即为INDEX_ID(page文件编号)
    [root@db212_21:29:54 /opt/undrop-for-innodb]  
    #./c_parser -4Df pages-ibdata1/FIL_PAGE_INDEX/0000000000000003.page -t dictionary/SYS_INDEXES.sql | grep '40'
    000000000521    3B0000014903A2  SYS_INDEXES 40  41  "PRIMARY"   1   3   0   4294967295
    SET FOREIGN_KEY_CHECKS=0;
    000000000521    3B0000014903A2  SYS_INDEXES 40  41  "PRIMARY"   1   3   0   4294967295
    
    • 用程序恢复字典信息:编辑mysql登录信息.
    [root@db212_21:57:04 /opt/undrop-for-innodb]  
    
    //将文件中三处mysql替换成/usr/local/mysql57/bin/mysql --login-path=p3507
    #vi recover_dictionary.sh 
     43 /usr/local/mysql57/bin/mysql --login-path=p3507 -e "CREATE DATABASE IF NOT EXISTS test"
    ...
     50 /usr/local/mysql57/bin/mysql --login-path=p3507 test < dictionary/$t.sql
    ...
     58 /usr/local/mysql57/bin/mysql --login-path=p3507 test < dumps/default/$t.sql 
    • 执行/recover_dictionary.sh,恢复字典信息
    [root@db212_22:13:57 /opt/undrop-for-innodb] 
    #./recover_dictionary.sh 
    Generating dictionary tables dumps... OK
    Creating test database ... OK
    Creating dictionary tables in database test:
    SYS_TABLES ... OK
    SYS_COLUMNS ... OK
    SYS_INDEXES ... OK
    SYS_FIELDS ... OK
    All OK
    Loading dictionary tables data:
    SYS_TABLES ... 52 recs OK
    SYS_COLUMNS ... 284 recs OK
    SYS_INDEXES ... 68 recs OK
    SYS_FIELDS ... 90 recs OK
    All OK
    [root@db212_22:14:02 /opt/undrop-for-innodb]  
    • 登录mysql查看信息字典信息:
    mysql --login-path=p3507
    root@localhost [(none)]>use test;
    Database changed
    root@localhost [test]>select * from SYS_TABLES where name like 'wenyz/t2%';
    +----------+----+--------+------+--------+---------+--------------+-------+
    | NAME     | ID | N_COLS | TYPE | MIX_ID | MIX_LEN | CLUSTER_NAME | SPACE |
    +----------+----+--------+------+--------+---------+--------------+-------+
    | wenyz/t2 | 40 |      3 |   33 |      0 |      64 |              |     0 |
    +----------+----+--------+------+--------+---------+--------------+-------+
    1 row in set (0.00 sec)
    
    root@localhost [test]>select * from SYS_INDEXES where table_id=40;
    +----------+----+---------+----------+------+-------+------------+
    | TABLE_ID | ID | NAME    | N_FIELDS | TYPE | SPACE | PAGE_NO    |
    +----------+----+---------+----------+------+-------+------------+
    |       40 | 41 | PRIMARY |        1 |    3 |     0 | 4294967295 |
    +----------+----+---------+----------+------+-------+------------+
    //注意记录上表中id,此ID为INDEX_ID(page文件编号)等会表数据恢复要使用
    1 row in set (0.00 sec)
    
    root@localhost [test]>
    ./sys_parser -h 127.0.0.1 -u root -p xxxx -d test wenyz/t2
    ./sys_parser: error while loading shared libraries: libmysqlclient.so.20: cannot open shared object file: No such file or directory
    #ln -s /opt/mysql-5.7.23-linux-glibc2.12-x86_64/lib/libmysqlclient.so.20 /usr/lib64/libmysqlclient.so.20 
    [root@db212_22:23:25 /opt/undrop-for-innodb]  
    #./sys_parser -h 127.0.0.1 -u root -p zstzst -d test wenyz/t2
    CREATE TABLE `t2`(
        `id` INT UNSIGNED NOT NULL,
        `ti` VARCHAR(100) CHARACTER SET 'utf8' COLLATE 'utf8_general_ci' NOT NULL,
        `date` DATE,
        PRIMARY KEY (`id`)
    ) ENGINE=InnoDB;
    [root@db212_22:23:30 /opt/undrop-for-innodb]  
    • 将恢复的表结构存到/tmp/t2.sql
    #cat /tmp/t2.sql
    CREATE TABLE `t2`(
        `id` INT UNSIGNED NOT NULL,
        `ti` VARCHAR(100) CHARACTER SET 'utf8' COLLATE 'utf8_general_ci' NOT NULL,
        `date` DATE,
        PRIMARY KEY (`id`)
    ) ENGINE=InnoDB;
    [root@db212_22:26:20 /opt/undrop-for-innodb]  
    

    5.表数据恢复 [ Top ]

    • 查看数据是否存在

    以下命令中使用的0000000000000041.page为上面提到的INDEX_ID(page文件编号),/tmp/t2.sql为上面恢复的表结构.

    [root@db212_22:33:44 /opt/undrop-for-innodb]  
    #./c_parser -6f pages-ibdata1/FIL_PAGE_INDEX/0000000000000041.page -t /tmp/t2.sql |head -2
    -- Page id: 459, Format: COMPACT, Records list: Valid, Expected records: (180 180)
    000000000507    A7000001210110  t2  4079859 "d553635af1a3b" "2018-08-04"
    000000000508    A8000001230110  t2  4079860 "44d64b99fc30d1b"   "2018-08-04"
    
    [root@db212_22:33:44 /opt/undrop-for-innodb]  
    • 利用c_parser将0000000000000041.page导出成可执行sql
    //注意:此处几个文件名程序把导出的两个数据文件的文件名关系是写死的,以下dumps/default/t2中的t2是需要和表名一致,在t2_load.sql中会引用此文件路经.
    ./c_parser -6f pages-ibdata1/FIL_PAGE_INDEX/0000000000000041.page -t /tmp/t2.sql > dumps/default/t2 2> dumps/default/t2_load.sql  
    #cd dumps/default/
    [root@db212_22:41:01 /opt/undrop-for-innodb/dumps/default]  
    #ll
    total 132
    -rw-r--r-- 1 root root 21232 Aug  4 22:14 SYS_COLUMNS
    ...
    -rw-r--r-- 1 root root 62923 Aug  4 22:40 t2
    -rw-r--r-- 1 root root   308 Aug  4 22:40 t2_load.sql
    [root@db212_22:41:04 /opt/undrop-for-innodb/dumps/default]  
    #cat t2_load.sql 
    SET FOREIGN_KEY_CHECKS=0;
    LOAD DATA LOCAL INFILE '/opt/undrop-for-innodb/dumps/default/t2' REPLACE INTO TABLE `t2` FIELDS TERMINATED BY '	' OPTIONALLY ENCLOSED BY '"' LINES STARTING BY 't2	' (`id`, `ti`, `date`);
    -- STATUS {"records_expected": 896, "records_dumped": 896, "records_lost": false} STATUS END
    • 将表结构t2.sql和表数据t2和t2_load.sql导入数据库
    root@localhost [test]>source /tmp/t2.sql
    Query OK, 0 rows affected (0.02 sec)
    
    root@localhost [test]>source /opt/undrop-for-innodb/dumps/default/t2_load.sql
    Query OK, 0 rows affected (0.00 sec)
    
    Query OK, 896 rows affected (0.01 sec)
    Records: 896  Deleted: 0  Skipped: 0  Warnings: 0
    
    root@localhost [test]>select count(*) from t2;
    +----------+
    | count(*) |
    +----------+
    |      896 |
    +----------+
    1 row in set (0.00 sec)
    
    root@localhost [test]>checksum table t2;
    +---------+------------+
    | Table   | Checksum   |
    +---------+------------+
    | test.t2 | 3458542072 |
    +---------+------------+
    1 row in set (0.00 sec)
    
    root@localhost [test]>
    
    //drop前数据信息对比:
    root@localhost [wenyz]>select count(*) from t2;
    +----------+
    | count(*) |
    +----------+
    |      896 |
    +----------+
    1 row in set (0.00 sec)
    
    root@localhost [wenyz]>checksum table t2;
    +----------+------------+
    | Table    | Checksum   |
    +----------+------------+
    | wenyz.t2 | 3458542072 |
    +----------+------------+
    1 row in set (0.00 sec)
    • 至此数据已经完全恢复.

    6.未解决的问题 [ Top ]

    问题1.
    innodb(非独立表空间)情况,drop表后,用工具读ibdata1对应数据页文件,如果是这个表大于350行左右的数据,页文件是存在的,但小于350行左右,页文件就不存在(drop前页文件是存在的).这是个什么原因呢
    脚本输出信息:

    以下为精简信息,完整输出信息请点击下载文本(由于不能上传txt,所以在文件名后面加了sh,下载后请删除.sh):
    320行,没有drop记录:
    320行,drop
    640行,drop

    
    select count(*) from t2
    640
    Table   Checksum
    wenyz.t2    1273189789
    ...
    -rw-r--r-- 1 root root   16384 Aug  4 23:09 0000000000000040.page
    -rw-r--r-- 1 root root   98304 Aug  4 23:09 0000000000000041.page /被drop表空间文件
    -rw-r--r-- 1 root root   16384 Aug  4 23:09 18446744069414584320.page
    
    count(*)320(行)
    Table   Checksum
    wenyz.t2    3018070873
    ....
    -rw-r--r-- 1 root root   16384 Aug  4 23:12 0000000000000038.page
    -rw-r--r-- 1 root root   32768 Aug  4 23:12 0000000000000039.page
    -rw-r--r-- 1 root root   16384 Aug  4 23:12 0000000000000040.page \这里缺41.page
    -rw-r--r-- 1 root root   16384 Aug  4 23:12 18446744069414584320.page

    把drop命令在脚本里注释后(还是320行)

    以下为精简信息,完整输出信息附后:
    #/tmp/init3507.sh
    BrI?Zu>o=1uN
    mysql: [Warning] Using a password on the command line interface can be insecure.
    root@localhost [(none)]>alter user user() identified by 'xxxxx';
    Query OK, 0 rows affected (0.00 sec)
    
    root@localhost [(none)]>exit
    Bye
    mysql: [Warning] Using a password on the command line interface can be insecure.
    count(*) ---------------------------------------------------------------------------------320行数据
    320
    Table   Checksum
    wenyz.t2    2368041617
    ...
    -rw-r--r-- 1 root root   32768 Aug  4 23:16 0000000000000039.page
    -rw-r--r-- 1 root root   16384 Aug  4 23:16 0000000000000040.page
    -rw-r--r-- 1 root root   32768 Aug  4 23:16 0000000000000041.page //320行时不drop是有此表空间文件的
    -rw-r--r-- 1 root root   16384 Aug  4 23:16 18446744069414584320.page
    [root@db211_23:16:21 /opt/undrop-for-innodb]  
    #
    
    • 为了快速测试数据恢复,使用的脚本
      init3507.sh
      /tmp/init3507.sh
    pkill mysqld
    rm -rf /3507/data/* /3507/logs/*
    /usr/local/mysql57/bin/mysqld --defaults-file=/3507/my3507.cnf --initialize-insecure
    /usr/local/mysql57/bin/mysqld --defaults-file=/3507/my3507.cnf&
    sleep 2
    /usr/local/mysql57/bin/mysql -S /tmp/mysql3507.sock -uroot  </tmp/create_t2.sql
    rm -rf /opt/undrop-for-innodb/pages-ibdata1
    #ls -l
    cd /opt/undrop-for-innodb/
    sleep 5
    rm -rf /opt/undrop-for-innodb/pages-ibdata1
    cd /opt/undrop-for-innodb/
    /opt/undrop-for-innodb/stream_parser -f /3507/data/ibdata1
    ls -l /opt/undrop-for-innodb/pages-ibdata1/FIL_PAGE_INDEX
    

    /tmp/create_t2.sql (由于不能上传sql文件,所以只能改为sh)

    alter user user() identified by 'xxxx';
    CREATE DATABASE wenyz;
    use wenyz;
    CREATE TABLE `t2` (
      `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
      `ti` varchar(100) NOT NULL,
      `date` date DEFAULT NULL,
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB AUTO_INCREMENT=4079859 DEFAULT CHARSET=utf8;
    insert into t2(ti,date) values(substring(MD5(RAND()),floor(RAND()*26)+1,15),now()) ;
    insert into t2(ti,date) values(substring(MD5(RAND()),floor(RAND()*26)+1,15),now()) ;
    insert into t2(ti,date) values(substring(MD5(RAND()),floor(RAND()*26)+1,15),now()) ;
    insert into t2(ti,date) values(substring(MD5(RAND()),floor(RAND()*26)+1,15),now()) ;
    insert into t2(ti,date) values(substring(MD5(RAND()),floor(RAND()*26)+1,15),now()) ;
    insert into t2(ti,date) values(substring(MD5(RAND()),floor(RAND()*26)+1,15),now()) ;
    insert into t2(ti,date) values(substring(MD5(RAND()),floor(RAND()*26)+1,15),now()) ;
    insert into t2(ti,date) values(substring(MD5(RAND()),floor(RAND()*26)+1,15),now()) ;
    insert into t2(ti,date) values(substring(MD5(RAND()),floor(RAND()*26)+1,15),now()) ;
    insert into t2(ti,date) values(substring(MD5(RAND()),floor(RAND()*26)+1,15),now()) ;
    insert into t2(ti,date) select ti,date from t2;
    insert into t2(ti,date) select ti,date from t2;
    insert into t2(ti,date) select ti,date from t2;
    insert into t2(ti,date) select ti,date from t2;
    insert into t2(ti,date) select ti,date from t2;
    select count(*) from t2;
    checksum table t2;
    drop table t2;
    

    7.参考过的资料 [ Top ]

    转自

    没有备份怎么恢复被drop的表(利用undrop-for-innodb) - 2森林 - 博客园 https://www.cnblogs.com/2woods/p/9420414.html

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  • 原文地址:https://www.cnblogs.com/paul8339/p/9910518.html
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