Mysql InnoDB 笔记 内存

InnoDB 状态

show engine innodb status\G;

    执行结果

Type: InnoDB
Name:
Status:
Per second averages calculated from the last 6 seconds
-----------------
BACKGROUND THREAD
-----------------
srv_master_thread loops: 0 srv_active, 0 srv_shutdown, 17509 srv_idle
srv_master_thread log flush and writes: 17509
----------
SEMAPHORES
----------
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
------------
TRANSACTIONS
------------
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
--------
FILE I/O
--------
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
-------------------------------------
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.
-------------------------------------
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 2122026419
Log flushed up to 2122026419
Pages flushed up to 2122026419
Last checkpoint at 2122026419
0 pending log writes, 0 pending chkp writes
8 log i/o's done, 0.00 log i/o's/second
----------------------
BUFFER POOL AND MEMORY
----------------------
Total memory allocated 135987200; in additional pool allocated 0
Dictionary memory allocated 32514
Buffer pool size 8192
Free buffers 7892
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]
--------------
ROW OPERATIONS
--------------
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
----------------------------
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.

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.