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Percona Data Recovery Tool for InnoDB工具恢复单表的案例
今天上班有个朋友询问我，相关Percona Data Recovery Tool for InnoDB恢复数据中的一些问题，比如说delete，没法恢复数据，原先做过类似的异常处理就，再次模拟了下相关的恢复操作流程，仅供学习使用；相关的配置工具策略网上很多，这里我就一笔带过了，不再进行详述，下面就开始梳理相关的细节问题；
[root@Mysql64 local]# mysql -uroot -prootWelcome to the MySQL monitor. Commands end with ; or /g.Your MySQL connection id is 33Server version: 5.5.28-log Source distributionType 'help;' or '/h' for help. Type '/c' to clear the buffer.mysql> create database gg;ERROR 1007 (HY000): Can't create database 'gg'; database existsmysql> show databases;+--------------------+| Database |+--------------------+| information_schema | | cacti | | gg | | mysql | | performance_schema | | temp | | test | +--------------------+7 rows in set (0.12 sec)mysql> use gg;Database changedmysql> show tables;Empty set (0.00 sec)mysql> create table a select * from mysql.user;Query OK, 12 rows affected (0.17 sec)Records: 12 Duplicates: 0 Warnings: 0mysql> delete from a;Query OK, 12 rows affected (0.12 sec)mysql> select * from a;Empty set (0.00 sec)mysql> [root@Mysql64 percona-data-recovery-tool-for-innodb-0.5]# ./page_parser -5 -f /usr/local/mysql/data/gg/a.ibd Opening file: /usr/local/mysql/data/gg/a.ibd:64768 ID of device containing file5836121 inode number33200 protection1 number of hard links500 user ID of owner500 group ID of owner0 device ID (if special file)98304 total size, in bytes4096 blocksize for filesystem I/O200 number of blocks allocated1377829472 time of last access1377831011 time of last modification1377831011 time of last status change98304 Size to process in bytes104857600 Disk cache size in bytes[root@Mysql64 percona-data-recovery-tool-for-innodb-0.5]#./create_defs.pl --host=localhost --user=root --password=root --db=gg --table=a > include/table_defs.h[root@Mysql64 percona-data-recovery-tool-for-innodb-0.5]# cat include/table_defs.h can_be_null: FALSE, uint_min_val: 0, uint_max_val: 4294967295ULL }, can_be_null: FALSE }, { /* char(64) */ name: "plugin", type: FT_CHAR, min_length: 64, max_length: 192, has_limits: FALSE, limits: { can_be_null: TRUE, char_min_len: 0, char_max_len: 192, char_ascii_only: TRUE }, can_be_null: TRUE }, { /* text */ name: "authentication_string", type: FT_TEXT, min_length: 0, max_length: 65535, has_limits: FALSE, limits: { can_be_null: TRUE, char_min_len: 0, char_max_len: 65535, char_ascii_only: TRUE }, can_be_null: TRUE }, { type: FT_NONE } } },};#endif[root@Mysql64 percona-data-recovery-tool-for-innodb-0.5]# [root@Mysql64 percona-data-recovery-tool-for-innodb-0.5]# ./constraints_parser -5 -D -f pages-1377849796/FIL_PAGE_INDEX/0-18/0-00000003.page LOAD DATA INFILE '/usr/local/percona-data-recovery-tool-for-innodb-0.5/dumps/default/SYS_TABLES' REPLACE INTO TABLE `SYS_TABLES` FIELDS TERMINATED BY '/t' OPTIONALLY ENCLOSED BY '"' LINES STARTING BY 'SYS_TABLES/t' (NAME, ID, N_COLS, TYPE, MIX_ID, MIX_LEN, CLUSTER_NAME, SPACE);[root@Mysql64 percona-data-recovery-tool-for-innodb-0.5]# makegcc -DHAVE_OFFSET64_T -D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE=1 -D_LARGEFILE_SOURCE=1 -Wall -O3 -g -I include -I mysql-source/include -I mysql-source/innobase/include -c tables_dict.c -o lib/tables_dict.ogcc -DHAVE_OFFSET64_T -D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE=1 -D_LARGEFILE_SOURCE=1 -Wall -O3 -g -I include -I mysql-source/include -I mysql-source/innobase/include -c print_data.c -o lib/print_data.o gcc -DHAVE_OFFSET64_T -D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE=1 -D_LARGEFILE_SOURCE=1 -Wall -O3 -g -I include -I mysql-source/include -I mysql-source/innobase/include -c check_data.c -o lib/check_data.ogcc -DHAVE_OFFSET64_T -D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE=1 -D_LARGEFILE_SOURCE=1 -Wall -O3 -g -I include -I mysql-source/include -I mysql-source/innobase/include -o constraints_parser constraints_parser.c lib/tables_dict.o lib/print_data.o lib/check_data.o lib/libut.a lib/libmystrings.agcc -DHAVE_OFFSET64_T -D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE=1 -D_LARGEFILE_SOURCE=1 -Wall -O3 -g -I include -I mysql-source/include -I mysql-source/innobase/include -static -lrt -o page_parser page_parser.c lib/tables_dict.o lib/libut.a [root@Mysql64 percona-data-recovery-tool-for-innodb-0.5]# 这里需要重新编译才可以生产，不能只变异一次，不然后期你会看不到数据都为空值的；记住这里需要进行2次make哦，不能少一次！[root@Mysql64 percona-data-recovery-tool-for-innodb-0.5]# ./constraints_parser -5 -f pages-1377849796/FIL_PAGE_INDEX/0-18/0-00000003.page a "localhost " "root " "*81F5E21E35407D884A6CD4A731AEBFB6AF209E1B" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "" 00 0 0 " " ""a "Mysql64 " "root " "*81F5E21E35407D884A6CD4A731AEBFB6AF209E1B" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "" 00 0 0 " " ""a "127.0.0.1 " "root " "*81F5E21E35407D884A6CD4A731AEBFB6AF209E1B" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "" 00 0 0 " " ""a "::1 " "root " "*81F5E21E35407D884A6CD4A731AEBFB6AF209E1B" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "" 00 0 0 " " ""a "localhost " " " " " "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "" 00 0 0 " " NULLa "Mysql64 " " " " " "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "" 00 0 0 " " NULLa "localhost " "cacti " "*43DD7940383044FBDE5B177730FAD3405BC6DAD7" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "" 00 0 0 " " NULLa "192.168.155.229 " "cacti " "*43DD7940383044FBDE5B177730FAD3405BC6DAD7" "N" "N" "N" "N" "N" "N" "N" "N" "Y" "N" "N" "N" "N" "N" "N" "Y" "N" "N" "N" "N" "Y" "N" "N" "N" "N" "N" "N" "N" "N" "" 00 0 0 " " NULLa "% " "cacti " "*43DD7940383044FBDE5B177730FAD3405BC6DAD7" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "N" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "" 00 0 0 " " NULLa "127.0.0.1 " "cacti " "*43DD7940383044FBDE5B177730FAD3405BC6DAD7" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "" 00 0 0 " " NULLa "*.* " "cacti " " " "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "" 00 0 0 " " NULLa "% " "root " "*81F5E21E35407D884A6CD4A731AEBFB6AF209E1B" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "" 00 0 0 " " NULLLOAD DATA INFILE '/usr/local/percona-data-recovery-tool-for-innodb-0.5/dumps/default/a' REPLACE INTO TABLE `a` FIELDS TERMINATED BY '/t' OPTIONALLY ENCLOSED BY '"' LINES STARTING BY 'a/t' (Host, User, Password, Select_priv, Insert_priv, Update_priv, Delete_priv, Create_priv, Drop_priv, Reload_priv, Shutdown_priv, Process_priv, File_priv, Grant_priv, References_priv, Index_priv, Alter_priv, Show_db_priv, Super_priv, Create_tmp_table_priv, Lock_tables_priv, Execute_priv, Repl_slave_priv, Repl_client_priv, Create_view_priv, Show_view_priv, Create_routine_priv, Alter_routine_priv, Create_user_priv, Event_priv, Trigger_priv, Create_tablespace_priv, ssl_type, @var_ssl_cipher, @var_x509_issuer, @var_x509_subject, max_questions, max_updates, max_connections, max_user_connections, plugin, authentication_string)SET ssl_cipher = UNHEX(@var_ssl_cipher), x509_issuer = UNHEX(@var_x509_issuer), x509_subject = UNHEX(@var_x509_subject);[root@Mysql64 percona-data-recovery-tool-for-innodb-0.5]# 结下了看到了我从ibd里面删除的数据，我要把它放到一个目录内，记住这里我需要放到含有mysql访问的目录内，原先我存放在tmp啊，data目录啊都不行，最后放在mysql权限内的目录就可以了；[root@Mysql64 percona-data-recovery-tool-for-innodb-0.5]# ./constraints_parser -5 -f pages-1377849796/FIL_PAGE_INDEX/0-18/0-00000003.page > /usr/local/mysql/data/find.sqlLOAD DATA INFILE '/usr/local/percona-data-recovery-tool-for-innodb-0.5/dumps/default/a' REPLACE INTO TABLE `a` FIELDS TERMINATED BY '/t' OPTIONALLY ENCLOSED BY '"' LINES STARTING BY 'a/t' (Host, User, Password, Select_priv, Insert_priv, Update_priv, Delete_priv, Create_priv, Drop_priv, Reload_priv, Shutdown_priv, Process_priv, File_priv, Grant_priv, References_priv, Index_priv, Alter_priv, Show_db_priv, Super_priv, Create_tmp_table_priv, Lock_tables_priv, Execute_priv, Repl_slave_priv, Repl_client_priv, Create_view_priv, Show_view_priv, Create_routine_priv, Alter_routine_priv, Create_user_priv, Event_priv, Trigger_priv, Create_tablespace_priv, ssl_type, @var_ssl_cipher, @var_x509_issuer, @var_x509_subject, max_questions, max_updates, max_connections, max_user_connections, plugin, authentication_string)SET ssl_cipher = UNHEX(@var_ssl_cipher), x509_issuer = UNHEX(@var_x509_issuer), x509_subject = UNHEX(@var_x509_subject);[root@Mysql64 percona-data-recovery-tool-for-innodb-0.5]# 查询目录的内容是否正确；[root@Mysql64 data]# pwd/usr/local/mysql/data[root@Mysql64 data]# ll -h | grep find*-rw-r--r-- 1 root root 3.9K 08-30 16:31 find.sql 看到是有数据的有3.9k左右大小，当然这里是测试数据量比较小(mysql.user的数据量)！[root@Mysql64 data]# [root@Mysql64 data]# vi find.sql ---看看内容；a "localhost " "root " "*81F5E21E35407D884A6CD4A731AEBFB6AF209E1B" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "" 0 0 0 0 " " ""a "Mysql64 " "root " "*81F5E21E35407D884A6CD4A731AEBFB6AF209E1B" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "" 0 0 0 0 " " ""a "127.0.0.1 " "root " "*81F5E21E35407D884A6CD4A731AEBFB6AF209E1B" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "" 0 0 0 0 " " ""a "::1 " "root " "*81F5E21E35407D884A6CD4A731AEBFB6AF209E1B" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "" 0 0 0 0 " " ""a "localhost " " " " " "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "" 0 0 0 0 " " NULLa "Mysql64 " " " " " "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "" 0 0 0 0 " " NULLa "localhost " "cacti " "*43DD7940383044FBDE5B177730FAD3405BC6DAD7" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "" 0 0 0 0 " " NULLa "192.168.155.229 " "cacti " "*43DD7940383044FBDE5B177730FAD3405BC6DAD7" "N" "N" "N" "N" "N" "N" "N" "N" "Y" "N" "N" "N" "N" "N" "N" "Y" "N" "N" "N" "N" "Y" "N" "N" "N" "N" "N" "N" "N" "N" "" 0 0 0 0 " " NULLa "% " "cacti " "*43DD7940383044FBDE5B177730FAD3405BC6DAD7" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "N" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "" 0 0 0 0 " " NULLa "127.0.0.1 " "cacti " "*43DD7940383044FBDE5B177730FAD3405BC6DAD7" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "N" "" 0 0 0 0 " " NULLa "*.* " "cacti " " " "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "" 0 0 0 0 " " NULLa "% " "root " "*81F5E21E35407D884A6CD4A731AEBFB6AF209E1B" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "Y" "" 0 0 0 0 " " NULL~~~~~~~~~~~[root@Mysql64 data]# 下面我们需要把sql文件内的文本load到我们的库内；这里我需要提出的是load的路径，要进行设置下； 上面我在导入的时候估计变量忘记设置，导致出现部分失误，这里需要做的同学注意下； mysql> use gg;Database changedmysql> select * from a;Empty set (0.00 sec)mysql> LOAD DATA INFILE '/usr/local/mysql/data/find.sql' REPLACE INTO TABLE `a` FIELDS TERMINATED BY '/t' OPTIONALLY ENCLOSED BY '"' LINES STARTING BY 'a/t' (Host, User, Password, Select_priv, Insert_priv, Update_priv, Delete_priv, Create_priv, Drop_priv, Reload_priv, Shutdown_priv, Process_priv, File_priv, Grant_priv, References_priv, Index_priv, Alter_priv, Show_db_priv, Super_priv, Create_tmp_table_priv, Lock_tables_priv, Execute_priv, Repl_slave_priv, Repl_client_priv, Create_view_priv, Show_view_priv, Create_routine_priv, Alter_routine_priv, Create_user_priv, Event_priv, Trigger_priv, Create_tablespace_priv, ssl_type, @var_ssl_cipher, @var_x509_issuer, @var_x509_subject, max_questions, max_updates, max_connections, max_user_connections, plugin, authentication_string) -> SET -> ssl_cipher = UNHEX(@var_ssl_cipher), -> x509_issuer = UNHEX(@var_x509_issuer), -> x509_subject = UNHEX(@var_x509_subject);Query OK, 12 rows affected (0.03 sec)Records: 12 Deleted: 0 Skipped: 0 Warnings: 0mysql> select * from a;+-----------------+-------+-------------------------------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+------------+--------------+------------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+--------+-----------------------+| Host | User | Password | Select_priv | Insert_priv | Update_priv | Delete_priv | Create_priv | Drop_priv | Reload_priv | Shutdown_priv | Process_priv | File_priv | Grant_priv | References_priv | Index_priv | Alter_priv | Show_db_priv | Super_priv | Create_tmp_table_priv | Lock_tables_priv | Execute_priv | Repl_slave_priv | Repl_client_priv | Create_view_priv | Show_view_priv | Create_routine_priv | Alter_routine_priv | Create_user_priv | Event_priv | Trigger_priv | Create_tablespace_priv | ssl_type | ssl_cipher | x509_issuer | x509_subject | max_questions | max_updates | max_connections | max_user_connections | plugin | authentication_string |+-----------------+-------+-------------------------------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+------------+--------------+------------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+--------+-----------------------+| localhost | root | *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | | | | | 0 | 0 | 0 | 0 | | | | Mysql64 | root | *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | | | | | 0 | 0 | 0 | 0 | | | | 127.0.0.1 | root | *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | | | | | 0 | 0 | 0 | 0 | | | | ::1 | root | *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | | | | | 0 | 0 | 0 | 0 | | | | localhost | | | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | | | | | 0 | 0 | 0 | 0 | | NULL | | Mysql64 | | | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | | | | | 0 | 0 | 0 | 0 | | NULL | | localhost | cacti | *43DD7940383044FBDE5B177730FAD3405BC6DAD7 | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | | | | | 0 | 0 | 0 | 0 | | NULL | | 192.168.155.229 | cacti | *43DD7940383044FBDE5B177730FAD3405BC6DAD7 | N | N | N | N | N | N | N | N | Y | N | N | N | N | N | N | Y | N | N | N | N | Y | N | N | N | N | N | N | N | N | | | | | 0 | 0 | 0 | 0 | | NULL | | % | cacti | *43DD7940383044FBDE5B177730FAD3405BC6DAD7 | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | N | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | | | | | 0 | 0 | 0 | 0 | | NULL | | 127.0.0.1 | cacti | *43DD7940383044FBDE5B177730FAD3405BC6DAD7 | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | | | | | 0 | 0 | 0 | 0 | | NULL | | *.* | cacti | | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | | | | | 0 | 0 | 0 | 0 | | NULL | | % | root | *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | | | | | 0 | 0 | 0 | 0 | | NULL | +-----------------+-------+-------------------------------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+------------+--------------+------------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+--------+-----------------------+12 rows in set (0.00 sec)mysql>
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Explain the InnoDB Buffer Pool and its importance for performance.Apr 19, 2025 am 12:24 AMInnoDBBufferPool reduces disk I/O by caching data and indexing pages, improving database performance. Its working principle includes: 1. Data reading: Read data from BufferPool; 2. Data writing: After modifying the data, write to BufferPool and refresh it to disk regularly; 3. Cache management: Use the LRU algorithm to manage cache pages; 4. Reading mechanism: Load adjacent data pages in advance. By sizing the BufferPool and using multiple instances, database performance can be optimized.
MySQL vs. Other Programming Languages: A ComparisonApr 19, 2025 am 12:22 AMCompared with other programming languages, MySQL is mainly used to store and manage data, while other languages such as Python, Java, and C are used for logical processing and application development. MySQL is known for its high performance, scalability and cross-platform support, suitable for data management needs, while other languages have advantages in their respective fields such as data analytics, enterprise applications, and system programming.
Learning MySQL: A Step-by-Step Guide for New UsersApr 19, 2025 am 12:19 AMMySQL is worth learning because it is a powerful open source database management system suitable for data storage, management and analysis. 1) MySQL is a relational database that uses SQL to operate data and is suitable for structured data management. 2) The SQL language is the key to interacting with MySQL and supports CRUD operations. 3) The working principle of MySQL includes client/server architecture, storage engine and query optimizer. 4) Basic usage includes creating databases and tables, and advanced usage involves joining tables using JOIN. 5) Common errors include syntax errors and permission issues, and debugging skills include checking syntax and using EXPLAIN commands. 6) Performance optimization involves the use of indexes, optimization of SQL statements and regular maintenance of databases.
MySQL: Essential Skills for Beginners to MasterApr 18, 2025 am 12:24 AMMySQL is suitable for beginners to learn database skills. 1. Install MySQL server and client tools. 2. Understand basic SQL queries, such as SELECT. 3. Master data operations: create tables, insert, update, and delete data. 4. Learn advanced skills: subquery and window functions. 5. Debugging and optimization: Check syntax, use indexes, avoid SELECT*, and use LIMIT.
MySQL: Structured Data and Relational DatabasesApr 18, 2025 am 12:22 AMMySQL efficiently manages structured data through table structure and SQL query, and implements inter-table relationships through foreign keys. 1. Define the data format and type when creating a table. 2. Use foreign keys to establish relationships between tables. 3. Improve performance through indexing and query optimization. 4. Regularly backup and monitor databases to ensure data security and performance optimization.
MySQL: Key Features and Capabilities ExplainedApr 18, 2025 am 12:17 AMMySQL is an open source relational database management system that is widely used in Web development. Its key features include: 1. Supports multiple storage engines, such as InnoDB and MyISAM, suitable for different scenarios; 2. Provides master-slave replication functions to facilitate load balancing and data backup; 3. Improve query efficiency through query optimization and index use.
The Purpose of SQL: Interacting with MySQL DatabasesApr 18, 2025 am 12:12 AMSQL is used to interact with MySQL database to realize data addition, deletion, modification, inspection and database design. 1) SQL performs data operations through SELECT, INSERT, UPDATE, DELETE statements; 2) Use CREATE, ALTER, DROP statements for database design and management; 3) Complex queries and data analysis are implemented through SQL to improve business decision-making efficiency.
MySQL for Beginners: Getting Started with Database ManagementApr 18, 2025 am 12:10 AMThe basic operations of MySQL include creating databases, tables, and using SQL to perform CRUD operations on data. 1. Create a database: CREATEDATABASEmy_first_db; 2. Create a table: CREATETABLEbooks(idINTAUTO_INCREMENTPRIMARYKEY, titleVARCHAR(100)NOTNULL, authorVARCHAR(100)NOTNULL, published_yearINT); 3. Insert data: INSERTINTObooks(title, author, published_year)VA
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Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software
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mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),
