Important components of MySQL InnoDB

InnoDB consists of several components

First, Innodb_buffer_pool:

1 It is primarily used to cache data and indexes (precisely because the tables in InnoDB are organized by a clustered index, so the data is not the leaf node of the index of the primary key).

Second, change buffer:

1 If the UPDATE statement is to update the record of the level two index, but the page on which the record is located is not in Innodb_buffer_pool, InnoDB will put this on the two-level index

The update action for the face page is cached to a specific region of innodb_buffer_pool (change buffer), and then if there is another transaction B to read this level two index page,

Because the page is not yet, in the Innodb_buffer_pool, so B transaction will first load the page into the Innodb_buffer_pool, this way the target page even enter Innodb_buffer_pool,

Next, you can update the index page based on the contents of the change buffer. This can save IO operations and improve performance.

2 of course other refresh machine (change in buffer changes in the disk) system is also some, for example, when MySQL is more idle, slow shutdown process will also refresh

Change the contents of buffer to disk

3 Monitoring Change Buffer

show engine InnoDB status;-------------------------------------INSERTBUFFER andADAPTIVE HASHINDEX-------------------------------------Ibuf:size1, the free listLen 0, SEG size2,0mergesmerged Operations:Insert 0,DeleteMark0,Delete 0Discarded operations:Insert 0,DeleteMark0,Delete 0HashTableSize34679, node Heap has0buffer (s) HashTableSize34679, node Heap has0buffer (s) HashTableSize34679, node Heap has0buffer (s) HashTableSize34679, node Heap has0buffer (s) HashTableSize34679, node Heap has0buffer (s) HashTableSize34679, node Heap has0buffer (s) HashTableSize34679, node Heap has0buffer (s) HashTableSize34679, node Heap has0buffer (s)0.00Hash searches/S0.00Non-Hash searches/s---LOG---LogSequence Number 24635311LogFlushed up to   24635311Pages flushed up to 24635311 LastCheckpointAt246353020PendingLogFlushes,0Pending CHKP writesTen LogI/O's done, 0.00 log I/O'S/Second

　　　　

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Important components of MySQL InnoDB