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mysql 系统表

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information_schema

 

 

二、sys库

1).sys库介绍

Mysql5.7版本自带4个数据库,information_schema、mysql、performance_schema、sys。Sys库所有的数据源来自:performance_schema。目标是把performance_schema的把复杂度降低,让DBA能更好的阅读这个库里的内容。让DBA更快的了解DB的运行情况。sys_开头是库里的配置表,sys_config用于sys schema库的配置

Sys库下有两种表:

sys系统库支持MySQL 5.6或更高版本,要完全访问sys系统库,用户必须具有以下权限:

对所有sys表和视图具有SELECT权限
对所有sys存储过程和函数具有EXECUTE权限
对sys_config表具有INSERT、UPDATE权限
对某些特定的sys系统库存储过程和函数需要额外权限,如,ps_setup_save()存储过程,需要临时表相关的权限
 

2).表清单

mysql> show tables;
±----------------------------------------------+
| Tables_in_sys |
±----------------------------------------------+
| host_summary |
| host_summary_by_file_io |
| host_summary_by_file_io_type |
| host_summary_by_stages |
| host_summary_by_statement_latency |
| host_summary_by_statement_type |
| innodb_buffer_stats_by_schema |
| innodb_buffer_stats_by_table |
| innodb_lock_waits |
| io_by_thread_by_latency |
| io_global_by_file_by_bytes |
| io_global_by_file_by_latency |
| io_global_by_wait_by_bytes |
| io_global_by_wait_by_latency |
| latest_file_io |
| memory_by_host_by_current_bytes |
| memory_by_thread_by_current_bytes |
| memory_by_user_by_current_bytes |
| memory_global_by_current_bytes |
| memory_global_total |
| metrics |
| processlist |
| ps_check_lost_instrumentation |
| schema_auto_increment_columns |
| schema_index_statistics |
| schema_object_overview |
| schema_redundant_indexes |
| schema_table_lock_waits |
| schema_table_statistics |
| schema_table_statistics_with_buffer |
| schema_tables_with_full_table_scans |
| schema_unused_indexes |
| session |
| session_ssl_status |
| statement_analysis |
| statements_with_errors_or_warnings |
| statements_with_full_table_scans |
| statements_with_runtimes_in_95th_percentile |
| statements_with_sorting |
| statements_with_temp_tables |
| sys_config |
| user_summary |
| user_summary_by_file_io |
| user_summary_by_file_io_type |
| user_summary_by_stages |
| user_summary_by_statement_latency |
| user_summary_by_statement_type |
| version |
| wait_classes_global_by_avg_latency |
| wait_classes_global_by_latency |
| waits_by_host_by_latency |
| waits_by_user_by_latency |
| waits_global_by_latency |
| x$host_summary |
| x$host_summary_by_file_io |
| x$host_summary_by_file_io_type |
| x$host_summary_by_stages |
| x$host_summary_by_statement_latency |
| x$host_summary_by_statement_type |
| x$innodb_buffer_stats_by_schema |
| x$innodb_buffer_stats_by_table |
| x$innodb_lock_waits |
| x$io_by_thread_by_latency |
| x$io_global_by_file_by_bytes |
| x$io_global_by_file_by_latency |
| x$io_global_by_wait_by_bytes |
| x$io_global_by_wait_by_latency |
| x$latest_file_io |
| x$memory_by_host_by_current_bytes |
| x$memory_by_thread_by_current_bytes |
| x$memory_by_user_by_current_bytes |
| x$memory_global_by_current_bytes |
| x$memory_global_total |
| x$processlist |
| x$ps_digest_95th_percentile_by_avg_us |
| x$ps_digest_avg_latency_distribution |
| x$ps_schema_table_statistics_io |
| x$schema_flattened_keys |
| x$schema_index_statistics |
| x$schema_table_lock_waits |
| x$schema_table_statistics |
| x$schema_table_statistics_with_buffer |
| x$schema_tables_with_full_table_scans |
| x$session |
| x$statement_analysis |
| x$statements_with_errors_or_warnings |
| x$statements_with_full_table_scans |
| x$statements_with_runtimes_in_95th_percentile |
| x$statements_with_sorting |
| x$statements_with_temp_tables |
| x$user_summary |
| x$user_summary_by_file_io |
| x$user_summary_by_file_io_type |
| x$user_summary_by_stages |
| x$user_summary_by_statement_latency |
| x$user_summary_by_statement_type |
| x$wait_classes_global_by_avg_latency |
| x$wait_classes_global_by_latency |
| x$waits_by_host_by_latency |
| x$waits_by_user_by_latency |
| x$waits_global_by_latency |
±----------------------------------------------+
101 rows in set (0.01 sec)
————————————————

3)表介绍

 1、视图表分类介绍

host : 以IP分组相关的统计信息
innodb : innodb buffer 相关信息
io : 数据内不同维度展的IO相关的信息
memory : 以IP,连接,用户,分配的类型分组及总的占用显示内存的使用
metrics : DB的内部的统计值
processlist : 线程相关的信息(包含内部线程及用户连接)
ps_ : 没有工具统计的一些变量(没看出来存在的价值)
schema : 表结构相关的信息,例如: 自增,索引, 表里的每个字段类型,等待的锁等等
session : 用户连接相关的信息
statement : 基于语句的统计信息(重店)
statements_ : 出错的语句,进行全表扫描, 运行时间超长,排序相等(重点)
user_ : 和host_开头的相似,只是以用户分组统计
wait : 等待事件,比较专业,难看懂。
waits : 以IP,用户分组统计出来的一些延迟事件,有一定的参考价值。

2、表格字段说明

host_summary

字段名           意义
host            从哪个服务器上连过来。如果是NULL,表示内部的进程
Statements         这台服务器共执行了多少语句
Statement_latency       这台服务器发来等待语句执行的时间
Statement_avg_latency    该服务器等待语句执行的平均时间
Table_scans        该服务器扫描表的次数(非全表)
File_io          该服务器IO事件请求的次数
File_io_latency       该服务器请求等待IO的时间
Current_connections    该服务器当前的连接数
Total_connections      该服务器总连接DB共连接多少次
Unique_user        该服务器上有几个不同用户名的账户连接过来
Current_memory      该服务器上当前连接等占用的内存
Total_memory_allocated    该服务器上的请求总共使用的内存

Io_global_by_file_by_bytes

字段名           意义
File           被操作的文件名
Count_read        总共有多少次读
Total_read        总共读了多少字节
Avg_read       平均每次读多少字节
Count_write        总共多少次写
Total_written       总共写了多少字节
Avg_write       平均每次写的字节大学
Total          读和写总共的IO大学
Write_pct        写占total里的百分比

 

User_summary

字段名             意义
User             客户端连接过来的用户名。如果是NULL,表示内部进程
Statements          该用户执行了多少SQL
Statement_latency      该用户执行SQL的总延迟时间
Statement_avg_latency   该用户执行SQL的平均延迟时间
Table_scans          该用户执行SQL时扫描表的次数
File_ios          该用户请求操作用掉的IO
File_io_latency       该用户请求操作的IO总延迟时间
Current_connections    该用户当前的连接数
Total_connections     该用户总的连接数
Unique_hosts          该用户从几个唯一的机器连接过来
Current_memory       该用户当前占用的内存
Total_memory_allocated   该用户总共申请到的内存(累加值)
 

Memory_global_total

Total_allocated server总共分配出去的内存(应该是server层)

 

Memory_by_thread_by_current_bytes

字段名           意义
Thread_id        内部线程ID可以和session中的thd_id关联
User            这个线程是哪个用户创建的
Current_count_used    当前使用的内存块还没有释放
Current_allocated     当前分配的内存大小(字节)而且没有被释放出来
Current_avg_alloc     平均分配的blocks
Current_max_alloc      当前线程分配的最多内存
Total_allocated      当前连总共分配的内存大小

Statement_analysis

字段名           意义
Query           归一化的SQL样子
Db            在哪个DB中执行。NULL表示在任何DB
Full_scan        全表扫描的次数
Exec_count       该SQL执行的总次数
Err_count        发生错误的次数
Warn_count         发生警告的次数
Total_latency       总共发生延迟的实际
Max_latency       最大延迟时间
Avg_latency      平均延迟时间
Lock_latency      因锁等待占用的总时间
Rows_sent         执行该SQL返回的总行数
Rows_sent_avg      执行该SQL平均返回的行数
Tmp_tables        该SQL形成内存临时表的总次数
Tmp_disk_tables    该SQL形成文件临时表的总次数
Rows_sorted      该SQL总共排序的行数
Sort_merge_passes   用于排序中合并的总次数
Digest           该语句的hash值
First_screen      该SQL最早出现的时间
Last_screen      该SQL最近出现的时间
Session和processlist视图基本一样,只是把后台线程过滤掉。

Innodb_buffer_stats_by_schema

字段名           意义
Object_schema       库名
Allocated         基于库分配的buffer pool大小
Data           基于schema实际缓存的数据大小
Pages          当前schema缓存的page数
Pages_hashed      Buffer pool中进行hash 索引的page
Pages_old        Buffer pool中的旧页,可能被置换出去
Rows_cached      Buffer pool中以行为单位的缓存


Innodb_buffer_stats_by_table和innodb_buffer_stats_by_schema基本一致。只是比上面多了个object_name指定表名。

4)使用示例

 1、查询资源使用情况

mysql> Select * from host_summary limit 1\G
*************************** 1. row ***************************
host: 192.168.0.124
statements: 4
statement_latency: 234.17 us
statement_avg_latency: 58.54 us
table_scans: 0
file_ios: 0
file_io_latency: 0 ps
current_connections: 0
total_connections: 2
unique_users: 1
current_memory: 0 bytes
total_memory_allocated: 0 bytes
1 row in set (0.03 sec)

mysql> Select * from memory_global_total;
±----------------+
| total_allocated |
±----------------+
| 143.38 MiB |
±----------------+
1 row in set (0.01 sec)
说明:内存部分,不包括innodbbuffer pool,只是server 层申请的内存

mysql> Select * from io_global_by_file_by_bytes limit 1\G
*************************** 1. row ***************************
file: @@datadir/ibdata1
count_read: 235
total_read: 5.69 MiB
avg_read: 24.78 KiB
count_write: 2129
total_written: 63.44 MiB
avg_write: 30.51 KiB
total: 69.12 MiB
write_pct: 91.77
1 row in set (0.01 sec)

mysql> Select * from user_summary limit 1\G
*************************** 1. row ***************************
user: root
statements: 375314
statement_latency: 4.32 h
statement_avg_latency: 41.40 ms
table_scans: 157158
file_ios: 142646
file_io_latency: 2.97 m
current_connections: 1
total_connections: 8043
unique_hosts: 2
current_memory: 0 bytes
total_memory_allocated: 0 bytes
1 row in set (0.01 sec)

2、查询连接及发送的SQL情况

mysql> select host, current_connections,statements from host_summary;
±--------------±--------------------±-----------+
| host | current_connections | statements |
±--------------±--------------------±-----------+
| 192.168.0.124 | 0 | 4 |
| localhost | 1 | 187728 |
±--------------±--------------------±-----------+
2 rows in set (0.01 sec)

mysql> select conn_id, user, current_statement, last_statement from session;
±--------±---------------±------------------------------------------------------------------±---------------+
| conn_id | user | current_statement | last_statement |
±--------±---------------±------------------------------------------------------------------±---------------+
| 10052 | root@localhost | select conn_id, user, current_ … t, last_statement from session | NULL |
±--------±---------------±------------------------------------------------------------------±---------------+
1 row in set (0.08 sec)
————————————————

3、查询系统里执行最多的TOP 10 SQL

mysql> select * from statement_analysis order by exec_count desc limit 10\G;
*************************** 1. row ***************************
query: INSERT INTO t1 VALUES (…)
db: mysqlslap
full_scan:
exec_count: 98041
err_count: 0
warn_count: 0
total_latency: 47.17 m
max_latency: 1.98 s
avg_latency: 28.87 ms
lock_latency: 7.68 s
rows_sent: 0
rows_sent_avg: 0
rows_examined: 0
rows_examined_avg: 0
rows_affected: 98041
rows_affected_avg: 1
tmp_tables: 0
tmp_disk_tables: 0
rows_sorted: 0
sort_merge_passes: 0
digest: 946acd9cdfe59ae300b995cf0698c7ce
first_seen: 2021-02-10 11:30:55
last_seen: 2021-02-10 11:54:28
*************************** 2. row ***************************
query: SELECT intcol1 , charcol1 FROM t1
db: mysqlslap
full_scan: *
…
————————————————

4、查询IO最高的表

mysql> select * from io_global_by_file_by_bytes limit 10;
±------------------------------------------±-----------±-----------±----------±------------±--------------±-----------±-----------±----------+
| file | count_read | total_read | avg_read | count_write | total_written | avg_write | total | write_pct |
±------------------------------------------±-----------±-----------±----------±------------±--------------±-----------±-----------±----------+
| @@datadir/ibdata1 | 235 | 5.69 MiB | 24.78 KiB | 2129 | 63.44 MiB | 30.51 KiB | 69.12 MiB | 91.77 |
| @@datadir/ib_logfile1 | 2 | 64.50 KiB | 32.25 KiB | 9972 | 25.25 MiB | 2.59 KiB | 25.31 MiB | 99.75 |
| @@datadir/ib_logfile0 | 5 | 4.00 KiB | 819 bytes | 5901 | 15.30 MiB | 2.66 KiB | 15.31 MiB | 99.97 |
| @@datadir/ibtmp1 | 0 | 0 bytes | 0 bytes | 72 | 12.94 MiB | 184.00 KiB | 12.94 MiB | 100.00 |
| @@datadir/test2/fi_finance_detail_old.ibd | 545 | 8.52 MiB | 16.00 KiB | 0 | 0 bytes | 0 bytes | 8.52 MiB | 0.00 |
| @@datadir/test2/fi_finance_detail.ibd | 454 | 7.09 MiB | 16.00 KiB | 0 | 0 bytes | 0 bytes | 7.09 MiB | 0.00 |
| @@datadir/test2/macro_data.ibd | 259 | 4.05 MiB | 16.00 KiB | 0 | 0 bytes | 0 bytes | 4.05 MiB | 0.00 |
| @@datadir/test2/stock_daily.ibd | 191 | 2.98 MiB | 16.00 KiB | 0 | 0 bytes | 0 bytes | 2.98 MiB | 0.00 |
| @@datadir/test2/macro_data_copy1.ibd | 190 | 2.97 MiB | 16.00 KiB | 0 | 0 bytes | 0 bytes | 2.97 MiB | 0.00 |
| @@datadir/mysql/innodb_index_stats.ibd | 6 | 96.00 KiB | 16.00 KiB | 36 | 576.00 KiB | 16.00 KiB | 672.00 KiB | 85.71 |
±------------------------------------------±-----------±-----------±----------±------------±--------------±-----------±-----------±----------+

 

5、查询延迟比较严重语句

mysql> select * from statement_analysis order by avg_latency desc limit 2;
±------------------------------------------------------------------±-----±----------±-----------±----------±-----------±--------------±------------±------------±-------------±----------±--------------±--------------±------------------±--------------±------------------±-----------±----------------±------------±------------------±---------------------------------±--------------------±--------------------+
| query | db | full_scan | exec_count | err_count | warn_count | total_latency | max_latency | avg_latency | lock_latency | rows_sent | rows_sent_avg | rows_examined | rows_examined_avg | rows_affected | rows_affected_avg | tmp_tables | tmp_disk_tables | rows_sorted | sort_merge_passes | digest | first_seen | last_seen |
±------------------------------------------------------------------±-----±----------±-----------±----------±-----------±--------------±------------±------------±-------------±----------±--------------±--------------±------------------±--------------±------------------±-----------±----------------±------------±------------------±---------------------------------±--------------------±--------------------+
| GRANT ALL PRIVILEGES ON `test1` . * TO ? @? | NULL | | 1 | 0 | 0 | 923.08 us | 923.08 us | 923.08 us | 461.00 us | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | b59b9848088068e714ba6de1bd813e9d | 2021-02-09 16:47:08 | 2021-02-09 16:47:08 |
| SELECT `t` . `THREAD_ID` AS `t … _NUMBER_OF_BYTES_USED` ) DESC | sys | * | 3 | 0 | 0 | 274.54 ms | 116.47 ms | 91.51 ms | 6.10 ms | 20 | 7 | 30939 | 10313 | 0 | 0 | 15 | 7 | 200 | 0 | b3ea91361b876a2dba55fdce3df2ee23 | 2021-02-13 07:59:57 | 2021-02-13 08:10:46 |
±------------------------------------------------------------------±-----±----------±-----------±----------±-----------±--------------±------------±------------±-------------±----------±--------------±--------------±------------------±--------------±------------------±-----------±----------------±------------±------------------±---------------------------------±--------------------±--------------------+
2 rows in set (0.00 sec)

6、查询使用了磁盘临时表的SQL语句

mysql> select db, query, tmp_tables,tmp_disk_tables from statement_analysis where tmp_tables>0 or tmp_disk_tables >0 order by (tmp_tables+tmp_disk_tables) desc limit 20;
±-------------------±------------------------------------------------------------------±-----------±----------------+
| db | query | tmp_tables | tmp_disk_tables |
±-------------------±------------------------------------------------------------------±-----------±----------------+
| sys | SELECT `t` . `THREAD_ID` AS `t … _NUMBER_OF_BYTES_USED` ) DESC | 15 | 7 |
| sys | SELECT IF ( `isnull` ( `perfor … _host_by_event_name` GROUP BY | 16 | 2 |
| sys | SELECT IF ( `isnull` ( `perfor … _user_by_event_name` GROUP BY | 9 | 1 |
| sys | SELECT IF ( ( `locate` ( ? , ` … . `COMPRESSED_SIZE` ) ) DESC | 4 | 3 |
| sys | SELECT IF ( ( `locate` ( ? , ` … . `COMPRESSED_SIZE` ) ) DESC | 4 | 3 |
| sys | SHOW TABLES | 5 | 0 |
| NULL | SHOW SCHEMAS | 4 | 0 |
| NULL | SHOW VARIABLES LIKE ? | 4 | 0 |
| sys | SHOW TABLES LIKE ? | 4 | 0 |
| sys | SHOW SCHEMAS | 3 | 0 |
| test2 | SHOW TABLES | 2 | 0 |
| mysql | SHOW SCHEMAS | 2 | 0 |
| test1 | SHOW TABLES | 2 | 0 |
| performance_schema | SHOW TABLES | 2 | 0 |
| sys | SELECT `sys` . `format_bytes` … summary_global_by_event_name` | 1 | 1 |
| test2 | SHOW SCHEMAS | 1 | 0 |
| mysql | SHOW TABLES | 1 | 0 |
| test1 | SHOW SCHEMAS | 1 | 0 |
| sys | SHOW VARIABLES LIKE ? | 1 | 0 |
| performance_schema | SHOW SCHEMAS | 1 | 0 |
±-------------------±------------------------------------------------------------------±-----------±----------------+
20 rows in set (0.00 sec)

7、查询占用了最多的buffer pool的表

mysql> select * from innodb_buffer_stats_by_table order by pages desc limit 10;
±--------------±----------------------±-----------±-----------±------±-------------±----------±------------+
| object_schema | object_name | allocated | data | pages | pages_hashed | pages_old | rows_cached |
±--------------±----------------------±-----------±-----------±------±-------------±----------±------------+
| test2 | fi_finance_detail_old | 8.48 MiB | 7.73 MiB | 543 | 0 | 201 | 23448 |
| test2 | fi_finance_detail | 7.06 MiB | 6.46 MiB | 452 | 0 | 75 | 17179 |
| test2 | macro_data | 4.02 MiB | 3.68 MiB | 257 | 0 | 225 | 45098 |
| test2 | stock_daily | 2.95 MiB | 2.68 MiB | 189 | 0 | 189 | 49946 |
| test2 | macro_data_copy1 | 2.94 MiB | 2.69 MiB | 188 | 0 | 188 | 34261 |
| InnoDB System | SYS_TABLES | 1.45 MiB | 1.27 MiB | 93 | 0 | 1 | 4234 |
| test1 | tb_9002 | 416.00 KiB | 316.07 KiB | 26 | 0 | 26 | 1352 |
| test2 | macro_policy | 288.00 KiB | 224.03 KiB | 18 | 0 | 18 | 155 |
| mysql | help_topic | 176.00 KiB | 126.44 KiB | 11 | 0 | 11 | 239 |
| test1 | tb_9001 | 144.00 KiB | 96.00 KiB | 9 | 0 | 9 | 295 |
±--------------±----------------------±-----------±-----------±------±-------------±----------±------------+
10 rows in set (0.03 sec)

8、查询每个库占用多少buffer pool

mysql> select * from innodb_buffer_stats_by_schema;
±--------------±-----------±-----------±------±-------------±----------±------------+
| object_schema | allocated | data | pages | pages_hashed | pages_old | rows_cached |
±--------------±-----------±-----------±------±-------------±----------±------------+
| test2 | 26.42 MiB | 23.85 MiB | 1691 | 0 | 928 | 86357 |
| test1 | 672.00 KiB | 464.52 KiB | 42 | 0 | 42 | 840 |
| mysql | 656.00 KiB | 245.75 KiB | 41 | 0 | 36 | 1267 |
| InnoDB System | 304.00 KiB | 98.92 KiB | 19 | 0 | 7 | 235 |
| sys | 16.00 KiB | 338 bytes | 1 | 0 | 1 | 6 |
±--------------±-----------±-----------±------±-------------±----------±------------+
5 rows in set (0.07 sec)

9、查询每个连接分配多少内存

mysql> select b.user, current_count_used,current_allocated, current_avg_alloc, current_max_alloc,total_allocated,current_statement from memory_by_thread_by_current_bytes a,session b where a.thread_id = b.thd_id;
±---------------±-------------------±------------------±------------------±------------------±----------------±------------------------------------------------------------------+
| user | current_count_used | current_allocated | current_avg_alloc | current_max_alloc | total_allocated | current_statement |
±---------------±-------------------±------------------±------------------±------------------±----------------±------------------------------------------------------------------+
| root@localhost | 0 | 0 bytes | 0 bytes | 0 bytes | 0 bytes | select b.user, current_count_u … b where a.thread_id = b.thd_id |
±---------------±-------------------±------------------±------------------±------------------±----------------±------------------------------------------------------------------+
1 row in set (0.12 sec)

 

10、查询MySQL内部现在有多个线程在运行

mysql> select user, count() from processlist group by user;
±--------------------------------±---------+
| user | count() |
±--------------------------------±---------+
| innodb/buf_dump_thread | 1 |
| innodb/dict_stats_thread | 1 |
| innodb/io_ibuf_thread | 1 |
| innodb/io_log_thread | 1 |
| innodb/io_read_thread | 4 |
| innodb/io_write_thread | 4 |
| innodb/page_cleaner_thread | 1 |
| innodb/srv_error_monitor_thread | 1 |
| innodb/srv_lock_timeout_thread | 1 |
| innodb/srv_master_thread | 1 |
| innodb/srv_monitor_thread | 1 |
| innodb/srv_purge_thread | 1 |
| innodb/srv_worker_thread | 3 |
| root@localhost | 1 |
| sql/compress_gtid_table | 1 |
| sql/main | 1 |
| sql/signal_handler | 1 |
| sql/thread_timer_notifier | 1 |
±--------------------------------±---------+
18 rows in set (0.08 sec)

 

 


原文链接:https://blog.csdn.net/carefree2005/article/details/113798841

标签:latency,系统,MiB,bytes,-----------,mysql,KiB,schema
来源: https://www.cnblogs.com/chengyunblogs/p/16244249.html