“响应时间”是衡量数据库性能的常用指标。在MariaDB中可以使用插件“QUERY_RESPONSE_TIME”来获取查询时间区间的统计信息。
// 安装插 件
$ cd ${mysql_base}/lib/plugin
$ ll
-rw-r--r--. 1 root root 403898 Feb 25 01:15 query_response_time.so
MariaDB [(none)]> install plugin query_response_time_audit soname 'query_response_time.so';
MariaDB [(none)]> install plugin query_response_time soname 'query_response_time.so';
MariaDB [(none)]> show plugins;
... | QUERY_RESPONSE_TIME_AUDIT | ACTIVE | AUDIT | query_response_time.so | GPL |
| QUERY_RESPONSE_TIME | ACTIVE | INFORMATION SCHEMA | query_response_time.so | GPL |
+-------------------------------+----------+--------------------+------------------------+---------+
// 参数说明
MariaDB [(none)]> show variables like 'query_response%';
+--------------------------------+-------+
| Variable_name | Value |
+--------------------------------+-------+
| query_response_time_flush | OFF |
| query_response_time_range_base | 10 |
| query_response_time_stats | OFF |
+--------------------------------+-------+
3 rows in set (0.00 sec)
query_response_time_flush
Description: Updating this variable flushes the statistics and re-reads query_response_time_range_base.
Commandline: None
Scope: Global
Dynamic: Yes
Data Type: boolean
Default Value: OFF
query_response_time_range_base
Description: Select base of log for QUERY_RESPONSE_TIME ranges. WARNING: variable change takes affect only after flush.
Commandline: --query-response-time-range-base=#
Scope: Global
Dynamic: Yes
Data Type: numeric
Default Value: 10
Range: 2 to 1000
if the range base=10, we have the following intervals:
(0; 10 ^ -6], (10 ^ -6; 10 ^ -5], (10 ^ -5; 10 ^ -4], ...,
(10 ^ -1; 10 ^1], (10^1; 10^2]...(10^7; positive infinity]
query_response_time_stats
Description: Enable or disable query response time statistics collecting
Commandline: query-response-time-stats[={0|1}]
Scope: Global
Dynamic: Yes
Data Type: boolean
Default Value: OFF
// 打开统计
MariaDB [(none)]> set global query_response_time_stats = 1;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> set global query_response_time_flush='ON';
Query OK, 0 rows affected (0.00 sec)
MariaDB [information_schema]> select * from information_schema.QUERY_RESPONSE_TIME;
+----------------+-------+----------------+
| TIME | COUNT | TOTAL |
+----------------+-------+----------------+
| 0.000001 | 0 | 0.000000 |
| 0.000010 | 0 | 0.000000 |
| 0.000100 | 70 | 0.002200 |
| 0.001000 | 16 | 0.005615 |
| 0.010000 | 0 | 0.000000 |
| 0.100000 | 0 | 0.000000 |
| 1.000000 | 0 | 0.000000 |
| 10.000000 | 0 | 0.000000 |
| 100.000000 | 0 | 0.000000 |
| 1000.000000 | 0 | 0.000000 |
| 10000.000000 | 0 | 0.000000 |
| 100000.000000 | 0 | 0.000000 |
| 1000000.000000 | 0 | 0.000000 |
| TOO LONG | 0 | TOO LONG |
+----------------+-------+----------------+
14 rows in set (0.00 sec)
// 分析
从上面的记录可知：
有70个查询的执行时间在0.000010秒<query execution time < =0.000100秒这个区间里；耗时总计0.002200秒。
有16个查询的执行时间在0.000100秒<query execution time < =0.001000秒这个区间里；耗时总计0.005615秒。