Percona Data Recovery Tool for InnoDB工具恢复单表的案例_MySQL
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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>登入後複製
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與MySQL中使用索引相比，全表掃描何時可以更快？
Apr 09, 2025 am 12:05 AM
全表掃描在MySQL中可能比使用索引更快，具體情況包括：1)數據量較小時；2)查詢返回大量數據時；3)索引列不具備高選擇性時；4)複雜查詢時。通過分析查詢計劃、優化索引、避免過度索引和定期維護表，可以在實際應用中做出最優選擇。
可以在 Windows 7 上安裝 mysql 嗎
Apr 08, 2025 pm 03:21 PM
是的，可以在 Windows 7 上安裝 MySQL，雖然微軟已停止支持 Windows 7，但 MySQL 仍兼容它。不過，安裝過程中需要注意以下幾點：下載適用於 Windows 的 MySQL 安裝程序。選擇合適的 MySQL 版本（社區版或企業版）。安裝過程中選擇適當的安裝目錄和字符集。設置 root 用戶密碼，並妥善保管。連接數據庫進行測試。注意 Windows 7 上的兼容性問題和安全性問題，建議升級到受支持的操作系統。
說明InnoDB全文搜索功能。
Apr 02, 2025 pm 06:09 PM
InnoDB的全文搜索功能非常强大，能够显著提高数据库查询效率和处理大量文本数据的能力。1）InnoDB通过倒排索引实现全文搜索，支持基本和高级搜索查询。2）使用MATCH和AGAINST关键字进行搜索，支持布尔模式和短语搜索。3）优化方法包括使用分词技术、定期重建索引和调整缓存大小，以提升性能和准确性。
InnoDB中的聚類索引和非簇索引（次級索引）之間的差異。
Apr 02, 2025 pm 06:25 PM
聚集索引和非聚集索引的區別在於：1.聚集索引將數據行存儲在索引結構中，適合按主鍵查詢和範圍查詢。 2.非聚集索引存儲索引鍵值和數據行的指針，適用於非主鍵列查詢。
mysql：簡單的概念，用於輕鬆學習
Apr 10, 2025 am 09:29 AM
MySQL是一個開源的關係型數據庫管理系統。 1）創建數據庫和表：使用CREATEDATABASE和CREATETABLE命令。 2）基本操作：INSERT、UPDATE、DELETE和SELECT。 3）高級操作：JOIN、子查詢和事務處理。 4）調試技巧：檢查語法、數據類型和權限。 5）優化建議：使用索引、避免SELECT*和使用事務。
mysql用戶和數據庫的關係
Apr 08, 2025 pm 07:15 PM
MySQL 數據庫中，用戶和數據庫的關係通過權限和表定義。用戶擁有用戶名和密碼，用於訪問數據庫。權限通過 GRANT 命令授予，而表由 CREATE TABLE 命令創建。要建立用戶和數據庫之間的關係，需創建數據庫、創建用戶，然後授予權限。
說明不同類型的MySQL索引（B樹，哈希，全文，空間）。
Apr 02, 2025 pm 07:05 PM
MySQL支持四種索引類型：B-Tree、Hash、Full-text和Spatial。 1.B-Tree索引適用於等值查找、範圍查詢和排序。 2.Hash索引適用於等值查找，但不支持範圍查詢和排序。 3.Full-text索引用於全文搜索，適合處理大量文本數據。 4.Spatial索引用於地理空間數據查詢，適用於GIS應用。
mysql 和 mariadb 可以共存嗎
Apr 08, 2025 pm 02:27 PM
MySQL 和 MariaDB 可以共存，但需要謹慎配置。關鍵在於為每個數據庫分配不同的端口號和數據目錄，並調整內存分配和緩存大小等參數。連接池、應用程序配置和版本差異也需要考慮，需要仔細測試和規劃以避免陷阱。在資源有限的情況下，同時運行兩個數據庫可能會導致性能問題。
