Innodb相关的一些参数

Innodb相关的一些有用的参数

今天就写写innodb相关的一些参数吧，如下：

首先是查看innodb的版本：

mysql 20:55:04>>show variables like '%innodb_version%';
+----------------+-----------+
| Variable_name  | Value     |
+----------------+-----------+
| innodb_version | 5.7.16-10 |
+----------------+-----------+
1 row in set (0.01 sec)

innodb中读写IO的线程个数：

mysql 20:55:19>>show variables like '%innodb_%io_thread%';
+-------------------------+-------+
| Variable_name           | Value |
+-------------------------+-------+
| innodb_read_io_threads  | 4     |
| innodb_write_io_threads | 4     |
+-------------------------+-------+
2 rows in set (0.00 sec)

innodb中用于回收undo页的purge线程个数：

mysql 20:58:12>>show variables like '%innodb_purge_thread%';
+----------------------+-------+
| Variable_name        | Value |
+----------------------+-------+
| innodb_purge_threads | 4     |
+----------------------+-------+
1 row in set (0.00 sec)

innodb中的buffer_pool的大小

mysql 20:59:38>>show variables like '%innodb_buffer_pool_size%';
+-------------------------+------------+
| Variable_name           | Value      |
+-------------------------+------------+
| innodb_buffer_pool_size | 1073741824 |
+-------------------------+------------+
1 row in set (0.00 sec)

innodb中缓冲池的个数：

mysql 21:00:48>>show variables like '%innodb_buffer_pool_instance%';
+------------------------------+-------+
| Variable_name                | Value |
+------------------------------+-------+
| innodb_buffer_pool_instances | 8     |
+------------------------------+-------+
1 row in set (0.01 sec)

观察各个缓冲池的状态的sql语法：

mysql 21:03:42>>select pool_id,pool_size,free_buffers,data _pages from information_schema.innodb_buffer_pool_stats;
+---------+-----------+--------------+----------------+
| pool_id | pool_size | free_buffers | data _pages |
+---------+-----------+--------------+----------------+
|       0 |      8191 |         7165 |            994 |
|       1 |      8191 |         7327 |            827 |
|       2 |      8191 |         7222 |            937 |
|       3 |      8191 |         7126 |           1030 |
|       4 |      8191 |         7114 |           1042 |
|       5 |      8191 |         7204 |            955 |
|       6 |      8191 |         7141 |           1015 |
|       7 |      8191 |         7211 |            948 |
+---------+-----------+--------------+----------------+
8 rows in set (0.00 sec)

查看innodb缓冲池中的LRU队列的中间点位置：

mysql 21:06:14>>show variables like '%innodb_old_blocks_pct%';
+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| innodb_old_blocks_pct | 37    |
+-----------------------+-------+
1 row in set (0.00 sec)

需要注意的是，这里的37是指37%的意思，也就是LRU列表的3/8处。

innodb中的redo log 缓冲：

mysql 21:06:24>>show variables like '%innodb_log_buffer_size%';                                                      +------------------------+----------+
| Variable_name          | Value    |
+------------------------+----------+
| innodb_log_buffer_size | 16777216 |
+------------------------+----------+
1 row in set (0.01 sec)

这个值一般设置为8M或者16M，我们只需要保证每秒产生的事务量在这个大小之内即可，因为每一秒种innodb会将重做日志缓冲刷新到日志文件中。

LRU列表中可用数据页的默认数量参数：

mysql 21:08:20>>show variables like '%innodb_lru_scan_depth%'; 
+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| innodb_lru_scan_depth | 1000  |
+-----------------------+-------+
1 row in set (0.00 sec)

当LRU列表中的数据页小于这个数量的时候，innodb会将LRU列表尾部的数据页移除

缓冲池中脏页所占用的百分比参数：

mysql 21:14:51>>show variables like '%innodb_max_dirty_pages_pct'; 
+----------------------------+-----------+
| Variable_name              | Value     |
+----------------------------+-----------+
| innodb_max_dirty_pages_pct | 75.000000 |
+----------------------------+-----------+
1 row in set (0.00 sec)

一旦脏页所占用的百分比大于这个数值，innodb将立即对缓冲池进行刷新到磁盘的操作。