mysql 性能定位,性能排查sql
Posted vincent2018
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##1.查询表的所属以及有多少行 SELECT TABLE_SCHEMA,TABLE_NAME,TABLE_ROWS FROM information_schema.`TABLES` WHERE TABLE_NAME=‘PRODUCT‘; ##2.查看当前应用连接,连接数突增排查 SELECT user,SUBSTRING_INDEX(HOST,‘:‘,1) as ip, count(*) as count, db FROM information_schema.`PROCESSLIST` WHERE `HOST` NOT IN (‘localhost‘) AND `USER` NOT IN(‘replicater‘) GROUP BY ip ORDER BY count; ##3.查看表碎片,是否需要整理表释放物理空间 SELECT TABLE_NAME,TABLE_ROWS ,concat(ROUND(DATA_LENGTH/1024/1024,2),‘MB‘) AS size, DATA_FREE/1024/1024 AS DATA_FREE_MB FROM information_schema.`TABLES` WHERE TABLE_SCHEMA=‘db库名‘ ORDER BY DATA_LENGTH DESC; ##4.当前有没有锁 SELECT * FROM information_schema.INNODB_LOCKS; ##5.当前锁堵塞情况 SELECT * FROM information_schema.INNODB_LOCK_WAITS; ##6.当前锁等待详细信息 select it.trx_mysql_thread_id, il.lock_id, il.lock_table, il.lock_mode, il.lock_type, it.trx_state, pl.USER||‘@‘||pl.HOST as user_host, pl.db, pl.command, pl.info, it.trx_started, it.trx_wait_started, now()-trx_wait_started as wait_seconds, il.lock_index, it.trx_weight, it.trx_rows_locked, it.trx_rows_modified from information_schema.INNODB_TRX it,information_schema.innodb_locks il,information_schema.processlist pl where it.trx_id = il.lock_trx_id and it.trx_mysql_thread_id = pl.id; ##7.最近一次死锁、未提交事物、CHECKPIONT、BUFFER POOL等 show engine innodb status; ##8.过滤无用线程信息可用pager show processlist; ##9.查看当前运行的详细SQL SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST WHERE info is not null; ##10.查看某条sql各阶段执行时间,可开启profiling功能 set global profiling=on; ##11.查看用户信息 select user,host,password from mysql.user group by user; ##12.分表时批量生成sql语句 select concat("select IP as ",TABLE_NAME," from ",TABLE_SCHEMA,".",TABLE_NAME," group by id;") from information_schema.TABLES where TABLE_NAME like ‘table_%‘; ##13.查看哪些sql执行最多 SELECT SCHEMA_NAME,DIGEST_TEXT,COUNT_STAR,SUM_ROWS_SENT,SUM_ROWS_EXAMINED,FIRST_SEEN,LAST_SEEN FROM performance_schema.events_statements_summary_by_digest where SCHEMA_NAME is not null and SCHEMA_NAME !=‘information_schema‘ ORDER BY COUNT_STAR desc LIMIT 1; ##14.哪个SQL平均响应时间最多 SELECT SCHEMA_NAME,DIGEST_TEXT,COUNT_STAR,AVG_TIMER_WAIT,SUM_ROWS_SENT,SUM_ROWS_EXAMINED,FIRST_SEEN,LAST_SEEN FROM performance_schema.events_statements_summary_by_digest where SCHEMA_NAME is not null and SCHEMA_NAME !=‘information_schema‘ ORDER BY AVG_TIMER_WAIT desc LIMIT 1; ##15.哪个SQL扫描的行数最多(IO消耗) SELECT SCHEMA_NAME,DIGEST_TEXT,COUNT_STAR,AVG_TIMER_WAIT,SUM_ROWS_SENT,SUM_ROWS_EXAMINED,FIRST_SEEN,LAST_SEEN FROM performance_schema.events_statements_summary_by_digest where SCHEMA_NAME is not null and SCHEMA_NAME !=‘information_schema‘ ORDER BY SUM_ROWS_EXAMINED desc LIMIT 1; ##16.哪个SQL使用的临时表最多 SELECT SCHEMA_NAME,DIGEST_TEXT,SUM_CREATED_TMP_DISK_TABLES,SUM_CREATED_TMP_TABLES,FIRST_SEEN,LAST_SEEN FROM performance_schema.events_statements_summary_by_digest where SCHEMA_NAME is not null and SCHEMA_NAME !=‘information_schema‘ ORDER BY SUM_CREATED_TMP_DISK_TABLES desc LIMIT 1; ##17.哪个SQL返回的结果集最多(net消耗) SELECT SCHEMA_NAME,DIGEST_TEXT,COUNT_STAR,SUM_ROWS_SENT,SUM_ROWS_SENT,FIRST_SEEN,LAST_SEEN FROM performance_schema.events_statements_summary_by_digest where SCHEMA_NAME is not null and SCHEMA_NAME !=‘information_schema‘ ORDER BY SUM_ROWS_SENT desc LIMIT 1; ##18.哪个SQL排序数最多(CPU消耗) SELECT SCHEMA_NAME,DIGEST_TEXT,COUNT_STAR,SUM_ROWS_SENT,SUM_SORT_ROWS,FIRST_SEEN,LAST_SEEN FROM performance_schema.events_statements_summary_by_digest where SCHEMA_NAME is not null and SCHEMA_NAME !=‘information_schema‘ ORDER BY SUM_SORT_ROWS desc LIMIT 5; #19.哪个表、文件逻辑IO最多(热数据) SELECT FILE_NAME,EVENT_NAME,COUNT_READ,SUM_NUMBER_OF_BYTES_READ,COUNT_WRITE,SUM_NUMBER_OF_BYTES_WRITE FROM performance_schema.file_summary_by_instance ORDER BY SUM_NUMBER_OF_BYTES_READ+SUM_NUMBER_OF_BYTES_WRITE DESC LIMIT 2; ##20.哪个索引使用最多 SELECT OBJECT_NAME, INDEX_NAME, COUNT_FETCH, COUNT_INSERT, COUNT_UPDATE, COUNT_DELETE FROM performance_schema.table_io_waits_summary_by_index_usage ORDER BY SUM_TIMER_WAIT DESC limit 1; ##21.哪个索引没有使用过 SELECT OBJECT_SCHEMA, OBJECT_NAME, INDEX_NAME FROM performance_schema.table_io_waits_summary_by_index_usage WHERE INDEX_NAME IS NOT NULL AND COUNT_STAR = 0 AND OBJECT_SCHEMA <> ‘mysql‘ ORDER BY OBJECT_SCHEMA,OBJECT_NAME; ##22.哪个等待事件消耗的时间最多 SELECT EVENT_NAME, COUNT_STAR, SUM_TIMER_WAIT, AVG_TIMER_WAIT FROM events_waits_summary_global_by_event_name WHERE event_name != ‘idle‘ ORDER BY SUM_TIMER_WAIT DESC LIMIT 1; ##23.通过performance_schema库得到数据库运行的统计信息,更好分析定位问题和完善监控信息 #打开标准的innodb监控: CREATE TABLE innodb_monitor (a INT) ENGINE=INNODB; #打开innodb的锁监控: CREATE TABLE innodb_lock_monitor (a INT) ENGINE=INNODB; #打开innodb表空间监控: CREATE TABLE innodb_tablespace_monitor (a INT) ENGINE=INNODB; #打开innodb表监控: CREATE TABLE innodb_table_monitor (a INT) ENGINE=INNODB; ##24.添加主键 alter table xxx add constraint primary key(id); ##25.删除外键 alter table test drop foreign key FK_XXX; ##26.QPS SHOW GLOBAL STATUS LIKE ‘Questions‘; SHOW GLOBAL STATUS LIKE ‘Uptime‘; #@27.TPS SHOW GLOBAL STATUS LIKE ‘Com_commit‘; SHOW GLOBAL STATUS LIKE ‘Com_rollback‘; SHOW GLOBAL STATUS LIKE ‘Uptime‘; (Com_commit + Com_rollback)/Uptime ##28. select table_name,table_rows,concat(round(DATA_LENGTH/1024/1024, 2), ‘MB‘) as size,DATA_FREE/1024/1024 AS data_free_MB from information_schema.TABLES where table_schema=‘库名‘ order by DATA_LENGTH desc; ##29.清理binlog PURGE BINARY LOGS TO ‘XXX‘; PURGE BINARY LOGS BEFORE ‘2018-06-10 00:00:00‘; ##30.外键隔离级别等信息 select @@FOREIGN_KEY_CHECKS; select @@global.tx_isolation,@@tx_isolation; select @@character_set_database; select @@GLOBAL.sql_mode;
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