什么叫做freeingitems

发布时间：2022-01-17 12:52 所属栏目：115 来源：互联网

导读：什么是freeingitems，很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。 show processlist 查看到大量的 freeing items状态会话查看官方文档，官方文档在8.14.2 General Thr

什么是freeingitems，很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。

show processlist 查看到大量的 freeing items状态会话

查看官方文档，官方文档在8.14.2 General Thread States章节给出了线程状态的解释

说明命令已经在执行正在进行清理更新日志索引等

mysql> SELECT @@profiling;
+-------------+
| @@profiling |
+-------------+
|           0 |
+-------------+
1 row in set (0.00 sec)
mysql> SET profiling = 1;
Query OK, 0 rows affected (0.00 sec)
mysql> DROP TABLE IF EXISTS t1;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> CREATE TABLE T1 (id INT);
Query OK, 0 rows affected (0.01 sec)
mysql> SHOW PROFILES;
+----------+----------+--------------------------+
| Query_ID | Duration | Query |
+----------+----------+--------------------------+
|        0 | 0.000088 | SET PROFILING = 1 |
|        1 | 0.000136 | DROP TABLE IF EXISTS t1 |
|        2 | 0.011947 | CREATE TABLE t1 (id INT) |
+----------+----------+--------------------------+
3 rows in set (0.00 sec)
mysql> SHOW PROFILE;
+----------------------+----------+
| Status           |      Duration |
+----------------------+----------+
| checking permissions | 0.000040 |
| creating table | 0.000056 |
| After create | 0.011363 |
| query end | 0.000375 |
| freeing items | 0.000089 |
| logging slow query | 0.000019 |
| cleaning up | 0.000005 |
+----------------------+----------+
7 rows in set (0.00 sec)
mysql> SHOW PROFILE FOR QUERY 1;
+--------------------+----------+
| Status | Duration |
+--------------------+----------+
| query end | 0.000107 |
| freeing items | 0.000008 |
| logging slow query | 0.000015 |
| cleaning up | 0.000006 |
+--------------------+----------+
4 rows in set (0.00 sec)
mysql> SHOW PROFILE CPU FOR QUERY 2;
+----------------------+----------+----------+------------+
| Status             | Duration | CPU_user | CPU_system |
+----------------------+----------+----------+------------+
| checking permissions | 0.000040 | 0.000038 | 0.000002 |
| creating table | 0.000056 | 0.000028 | 0.000028 |
| After create | 0.011363 | 0.000217 | 0.001571 |
| query end | 0.000375 | 0.000013 | 0.000028 |
| freeing items | 0.000089 | 0.000010 | 0.000014 |
| logging slow query | 0.000019 | 0.000009 | 0.000010 |
| cleaning up     | 0.000005 | 0.000003 | 0.000002 |
2662
SHOW Statements
+----------------------+----------+----------+------------+
7 rows in set (0.00 sec)
最后看宿主机的监控状态，load达到了 50多

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