MysqlInnoDB笔记内存_MySQL

Mysql InnoDB笔记内存

InnoDB 状态

Sql代码

show engine innodb status/G;

执行结果

Type: InnoDB

Name:

Status:

Per second averages calculated from the last 6 seconds

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BACKGROUND THREAD

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srv_master_thread loops: 0 srv_active, 0 srv_shutdown, 17509 srv_idle

srv_master_thread log flush and writes: 17509

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SEMAPHORES

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OS WAIT ARRAY INFO: reservation count 2

OS WAIT ARRAY INFO: signal count 2

Mutex spin waits 5, rounds 12, OS waits 0

RW-shared spins 2, rounds 60, OS waits 2

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

Spin rounds per wait: 2.40 mutex, 30.00 RW-shared, 0.00 RW-excl

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TRANSACTIONS

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Trx id counter 17154

Purge done for trx's n:o < 14771 undo n:o < 0 state: running but idle

History list length 588

LIST OF TRANSACTIONS FOR EACH SESSION:

---TRANSACTION 0, not started

MySQL thread id 1, OS thread handle 0x8ac, query id 15 localhost 127.0.0.1 root

init

show engine innodb status

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FILE I/O

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I/O thread 0 state: wait Windows aio (insert buffer thread)

I/O thread 1 state: wait Windows aio (log thread)

I/O thread 2 state: wait Windows aio (read thread)

I/O thread 3 state: wait Windows aio (read thread)

I/O thread 4 state: wait Windows aio (read thread)

I/O thread 5 state: wait Windows aio (read thread)

I/O thread 6 state: wait Windows aio (write thread)

I/O thread 7 state: wait Windows aio (write thread)

I/O thread 8 state: wait Windows aio (write thread)

I/O thread 9 state: wait Windows aio (write thread)

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

ibuf aio reads: 0, log i/o's: 0, sync i/o's: 0

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

312 OS file reads, 5 OS file writes, 5 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 性能 插入缓冲与自适应哈希 插入缓冲不是缓冲池的一部分.它使用于索引是辅助索引,且索引不是唯一的.因为如主键自增长则插入这个聚集索引按顺序插入很快完成,但是如表另有不是唯一的非聚集索引,就需要对非聚集索引的叶子节点插入离散存储B+树.

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Ibuf: size 1, free list len 0, seg size 2, 0 merges segSize:当前插入缓冲大小为2*16KB. free list 为空闲列表长度 size 为 已合并记录页为数量 insert 为插入记录数,merged 合并的页数量,merges合并次数

merged operations:

insert 0, delete mark 0, delete 0

discarded operations:

insert 0, delete mark 0, delete 0

Hash table size 553253, node heap has 1 buffer(s)

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

---

LOG

---

Log sequence number 21220219

Log flushed up to 21220219

Pages flushed up to 21220219

Last checkpoint at 21220219

0 pending log writes, 0 pending chkp writes

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

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BUFFER POOL AND MEMORY

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Total memory allocated 135987200; in additional pool allocated 0

Dictionary memory allocated 32514

Buffer pool size 8192

Free buffers 72

Database pages 299

Old database pages 0

Modified db pages 0

Pending reads 0

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

Pages made young 0, not young 0

0.00 youngs/s, 0.00 non-youngs/s

Pages read 299, created 0, written 1

0.00 reads/s, 0.00 creates/s, 0.00 writes/s

No buffer pool page gets since the last printout

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

LRU len: 299, unzip_LRU len: 0

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

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ROW OPERATIONS

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0 queries inside InnoDB, 0 queries in queue

0 read views open inside InnoDB

Main thread id 2708, state: sleeping

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

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

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

InnoDB的内存

由缓冲池,重做日志缓冲池及额外的内存构成.

Sql代码

show variables like 'innodb_buffer_pool_size'/G; 134217728

show variables like 'innodb_log_buffer_size'/G; 8388608

show variables like 'innodb_additional_mem_pool_size'/G; 8388608

缓冲池是最大的部分,用来存放各种数据的缓存.引擎按页16KB/每页读取到缓冲池,然后按LRU保留缓冲池中的数据.如果数据库文件需要修改,先修改缓冲池中的页,修改后即为脏页,然后按一定的频率将脏页刷新到文件.

Buffer pool size 8192 中的大小即可算出缓冲区 8192*16(KB/page)/1024 =?

缓冲池中缓存的数据类型有:索引页,数据页,UNDO页,插入缓冲,自适应哈希索引,InnoDB锁信息,数据字典等.

AWE 开启后引擎自动禁用自适应哈希索引.

日志缓冲将重做日志信息先放入这个缓冲区,再按一定的频率将其刷新到重做日志文件.