show engine innodb status 解读

Posted 2020-10-25

mysql> show engine innodb status\G

*************************** 1. row ***************************

  Type: InnoDB

  Name: 

Status: 

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2018-02-24 18:15:52 0x7f2ac00dd700 INNODB MONITOR OUTPUT

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Per second averages calculated from the last 41 seconds

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BACKGROUND THREAD

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srv_master_thread loops: 2 srv_active, 0 srv_shutdown, 23859 srv_idle

srv_master_thread log flush and writes: 23860

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SEMAPHORES

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OS WAIT ARRAY INFO: reservation count 2

OS WAIT ARRAY INFO: signal count 2

RW-shared spins 0, rounds 4, OS waits 2

RW-excl spins 0, rounds 0, OS waits 0

RW-sx spins 0, rounds 0, OS waits 0

Spin rounds per wait: 4.00 RW-shared, 0.00 RW-excl, 0.00 RW-sx

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LATEST FOREIGN KEY ERROR

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2018-01-29 23:23:31 0x7f984875e700 Transaction:

TRANSACTION 171061511, ACTIVE 1 sec inserting

mysql tables in use 1, locked 1

10 lock struct(s), heap size 1136, 6 row lock(s), undo log entries 5

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LATEST DETECTED DEADLOCK                ###  如果有死锁发生，会有相关的记录

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2018-02-24 18:52:09 2b6677e07700   -- 死锁发生的时间

*** (1) TRANSACTION:

*** (2) TRANSACTION:  --  事务2的状态

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TRANSACTIONS        ### 包含了InnoDB事务(transaction)的统计信息

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Trx id counter 5892

Purge done for trx's n:o < 5386 undo n:o < 0 state: running but idle

History list length 3

LIST OF TRANSACTIONS FOR EACH SESSION:

---TRANSACTION 421297007339344, not started

0 lock struct(s), heap size 1136, 0 row lock(s)

-------- 

FILE I/O   ###显示了I/O  Helper thread d的状态，包含一些统计信息

--------

I/O thread 0 state: waiting for completed aio requests (insert buffer thread)

I/O thread 1 state: waiting for completed aio requests (log thread)

I/O thread 2 state: waiting for completed aio requests (read thread)

I/O thread 3 state: waiting for completed aio requests (read thread)

I/O thread 4 state: waiting for completed aio requests (read thread)

I/O thread 5 state: waiting for completed aio requests (read thread)

I/O thread 6 state: waiting for completed aio requests (write thread)

I/O thread 7 state: waiting for completed aio requests (write thread)

I/O thread 8 state: waiting for completed aio requests (write thread)

I/O thread 9 state: waiting for completed aio requests (write thread)

Pending normal aio reads: [0, 0, 0, 0] , aio writes: [0, 0, 0, 0] ,

 ibuf aio reads:, log i/o's:, sync i/o's:

Pending flushes (fsync) log: 0; buffer pool: 0

384 OS file reads, 59 OS file writes, 7 OS fsyncs

0.00 reads/s, 0 avg bytes/read, 0.00 writes/s, 0.00 fsyncs/s

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INSERT BUFFER AND ADAPTIVE HASH INDEX

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Ibuf: size 1, free list len 0, seg size 2, 0 merges

merged operations:

 insert 0, delete mark 0, delete 0

discarded operations:

 insert 0, delete mark 0, delete 0

Hash table size 34679, node heap has 0 buffer(s)

Hash table size 34679, node heap has 0 buffer(s)

Hash table size 34679, node heap has 0 buffer(s)

Hash table size 34679, node heap has 0 buffer(s)

Hash table size 34679, node heap has 0 buffer(s)

Hash table size 34679, node heap has 0 buffer(s)

Hash table size 34679, node heap has 0 buffer(s)

Hash table size 34679, node heap has 0 buffer(s)

0.00 hash searches/s, 0.00 non-hash searches/s

---

LOG  ###记录了transaction log 子系统的信息

---

Log sequence number 370441977

Log flushed up to   370441977

Pages flushed up to 370441977

Last checkpoint at  370441968

0 pending log flushes, 0 pending chkp writes

10 log i/o's done, 0.00 log i/o's/second

----------------------

BUFFER POOL AND MEMORY          #####INNODB BUFFER POOL 状态，

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Total large memory allocated 137428992  --分配给innodb 的总内存大小、单位byte

Dictionary memory allocated 147231      --分配给innodb 数据字典的内存大小、单位byte

Buffer pool size   8192                 --innodb buffer pool的大小、单位page  如果page的大小设置为16k的话 *16*1024 = innodb_buffer_pool_size

Free buffers       7914                 --innodb buffer pool中空闲页面的数量，单位page

Database pages     278                  --innodb buffer pool中非空闲页面的数量, 单位page

Old database pages 0                    --old 子列表中的页面数量，单位page

Modified db pages  0                    --当前buffer pool中被修改的页面数量，单位page

Pending reads      0                    -- 数据由磁盘读到buffer pool，被挂起的次数

Pending writes: LRU 0, flush list 0, single page 0

Pages made young 0, not young 0        --Pages made young页面由old列表移动到new列表的次数;not young 页面由new列表移动表old列表的次数

0.00 youngs/s, 0.00 non-youngs/s       --youngs/s平均每秒有多少个页面由old移动到new,non-youngs/s平均每秒有多少个页面由new移动到old

Pages read 243, created 35, written 42   -- 从buffer pool中读出页面的总数;在innodb buffer pool中创建页面的总数; innodb buffer pool中被写过的页面总数

0.00 reads/s, 0.14 creates/s, 42.14 writes/s  -- 平均每秒从innodb buffer pool中读多少页,平均每秒innodb buffer pool要创建多少页,平均每少innodb buffer pool有多少页面被写

Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000   --　innodb buffer pool 命中率

Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s

--  Pages read ahead 平均每秒read ahead的次数  ,evicted without access平均每秒页面淘汰的次数 ,　 Random read ahead 平均每秒random read ahead的次数

LRU len: 80675, unzip_LRU len: 0

I/O sum[10392]:cur[0], unzip sum[0]:cur[0]

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INDIVIDUAL BUFFER POOL INFO   #############如设置了innodb_buffer_pool_instances，则有多个子pool

----------------------

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ROW OPERATIONS

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0 queries inside InnoDB, 0 queries in queue

0 read views open inside InnoDB

Process ID=2969, Main thread ID=139821729601280, state: sleeping

Number of rows inserted 0, updated 0, deleted 0, read 12

0.00 inserts/s, 0.00 updates/s, 0.00 deletes/s, 0.00 reads/s

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END OF INNODB MONITOR OUTPUT

============================

1 row in set (0.00 sec)

mysql> \s

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mysql  Ver 14.14 Distrib 5.7.20, for Linux (x86_64) using  EditLine wrapper
Connection id:4
Current database:performance_schema
Current user:[email protected]
SSL:Not in use
Current pager:stdout
Using outfile:''
Using delimiter:;
Server version:5.7.20-log MySQL Community Server (GPL)
Protocol version:10
Connection:Localhost via UNIX socket
Server characterset:utf8
Db     characterset:utf8
Client characterset:utf8
Conn.  characterset:utf8
UNIX socket:/var/lib/mysql/mysql.sock
Uptime:7 hours 28 min 8 sec
Threads: 3  Questions: 222  Slow queries: 0  Opens: 201  Flush tables: 1  Open tables: 194  Queries per second avg: 0.008
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