mysql pocket reference

Cache Fragmentation rate = 20.46%, query cache utilization = 62.26%, query cache Hit Ratio = 1.94%, hit ratio is poor, probably write more frequently, and possibly some fragments.======================================================================================== Sort Usage mysql> Show Global status like ' sort% ';Sort_merge_passes 2Sort_range 18528Sort_rows 390838Sort_scan 3439 MySQL first tries to so

-# Cmake-dcmake_install_prefix=/u01/app/mysql-dmysql_unix_addr=/tmp/mysql.sock-ddefault_charset=utf8-ddefault_ Collation=utf8_general_ci-dwith_extra_charsets=utf8,gbk-dwith_perfschema_storage_engine=1-dwith_federated_storage_engine=1-dwith_partition_storage_engine=1-dwith_archive_storage_engine=1-dmysql_datadir=/u01/app/mysqldata/data3306/-dsysconfdir=/u01/app/mysql/-dwith_ssl=bundled-denabled_local_ infi

mysql| Reference | reference Manual | chinese MySQL Chinese reference manual (catalog) Reprinted translator: Yan Zi return 〗〖 Forwarding Translator: Yan Zi (clyan@sohu.com) Homepage: http://linuxdb.yeah.net 0 Translator Preface 1 General information of the

MySQL database s Tudent table)Mysqldump.exe-u root-p mysql > mysql_bak.sql (Backup Database for all tables in MySQL)Restoring a DatabaseC:\Program files\mysql\mysql Server 5.5\bin>mysql-u root-p

Label:If Table A's primary key is a field in table B, the field is called the Foreign key of Table B, table A is called the primary table, and table B is called from the table. Foreign keys are used to achieve referential integrity, and different foreign key constraints will allow the two tables to be tightly combined, especially if the modified or deleted cascade operation will make routine maintenance easier. Here we take MySQL as an example to summ

Referentialintegrity is an important concept in database design. In different lists of systems, the integrity of the reference is involved when all references of the database are legal or illegal. When the integrity of the reference exists, any association with the non-existent reCord becomes invalid, which prevents various errors and provides a more accurate and practical database. Integrity of

"journalctl -xe" for details.这个错误有很多原因，通常我们有几种不同的办法来排查：1. 根据提示，在 root 权限下输入 systemctl status mysql.service 以及 journalctl -xe 来查看日志错误信息2. 如果上述日志不能明确指出问题，还可以在 terminal 中输入 mysql --help对于我的这次错误而言，是我在 /etc/mysql/my.cnf 中添加了一些错误的配置，使用 mysql --help 时提示出了错误的位置（精确到了行），因此问题得以解决。4. MySQL Linux下的配置文件及其位置众所周知，windows下

to check and remove duplicate indexes. Periodically use the Pt-index-usage tool to check and remove low-frequency indexes; 5, the regular collection slow query log, with the Pt-query-digest tool analysis, can be combined with anemometer system slow query management in order to analyze slow query and follow-up optimization work; 6, can use Pt-kill kill long time of SQL request, Percona version has an option innodb_kill_idle_transaction also can realize this function; 7, using Pt-online-schema-ch

Pool Size: The maximum number of threads allowed in a thread pool, default 100Connectionreset: If the connection expires automatically reset, default FalseCharacterSet, CharSet: The character set used to request a connection to the server, default: NoneTreatblobsasutf8:binary blobs is treated as UTF8, default falseBlobasutf8includepattern: The matching mode of the column, once the match will be processed by UTF8, default: NoneSslmode: Whether SSL connection mode is enabled, default: Mysqlsslmod

Globalmmm_infohost=db2_ipuser= ' root ' password= ' xxxxxx ' cmd= ' mmm_controlshow ' s=paramiko. Sshclient () s.load_system_host_keys () s.set_missing_host_key_policy (Paramiko . Autoaddpolicy ()) s.connect (host,22,user,password,timeout=1) stdin,stdout,stderr =s.exec_command (CMD) cmd_result=stdout.read (), Stderr.read () mmm_ Info=str (List (Cmd_result) [0]) defrun (IP): mmm_status () db_info (IP) ife== "":ifios!= "yes" orsqs! = "Yes": db_info= '%sreplicaitonerror!\nslave_io_ running:%s\nsl

solve the data consistency problem, high availability is incidentally implemented. Because PXC has write enlargement and short board effect, the concurrency efficiency will have a large loss, similar to the semi sync replication mechanism.Other high-availability scenarios Based on NDB Cluster, there are still many defects and limitations in NDB, and it is not recommended to use in production environment. Based on shared storage, on the one hand, the need for a less poor storage dev

search index in 8-9 seconds!Test again: search (id, vtype) or select id statement, also very sorry, 0.5 seconds.To sum up, if you want to reference limit with the where condition, you must design an indexPut first, the primary key used by limit is put 2nd bits, and only the select primary key can be used! Solved the paging problem perfectly. If you can quickly return the id, there is hope to optimize the limit. According to this logic, millions of li

from collect where vtype = 1 limit 90000,10; very sorry, 8-9 seconds, did not go to the search index!Test again: Search (ID, vtype) or select ID statement, also very sorry, 0.5 seconds. To sum up, if you want to reference limit with the where condition, you must design an index and place where first. The primary key used by limit is placed at 2nd bits, and only the select primary key can be used!Solved the paging problem perfectly. If you can quickl