打开mysql慢查询日志，发现有很多sql查询时间很短，明显不到0.01s的sql竟然也在慢日志查询里面，日志详细情况如下：
# User@Host: otterpro[otterpro] @ [172.22.53.122] Id: 2061
# Schema: otter Last_errno: 0 Killed: 0
# Query_time: 0.000559 Lock_time: 0.000080 Rows_sent: 3 Rows_examined: 327 Rows_affected: 0
# Bytes_sent: 755
SET timestamp=1512715920;
select ID,NODE_ID,PIPELINE_ID,LOCATION,GMT_CREATE,GMT_MODIFIED from PIPELINE_NODE_RELATION where NODE_ID = 74 ORDER BY ID DESC;
# Time: 171208 14:52:08
# User@Host: otterpro[otterpro] @ [172.22.53.122] Id: 2061
# Schema: otter Last_errno: 0 Killed: 0
# Query_time: 0.000214 Lock_time: 0.000110 Rows_sent: 2 Rows_examined: 2 Rows_affected: 0
# Bytes_sent: 821
SET timestamp=1512715928;
select ID,CLUSTER_NAME,SERVER_LIST,DESCRIPTION,GMT_CREATE,GMT_MODIFIED from AUTOKEEPER_CLUSTER ORDER BY ID ASC;
有点怀疑再次查看了参数：
+---------------+---------+
| Variable_name | Value |
+---------------+---------+
| Slow_queries | 6055683 |
+---------------+---------+
mysql> show variables like '%slow_query_log%';
+------------------------------------+--------------------------------+
| Variable_name | Value |
+------------------------------------+--------------------------------+
| slow_query_log | ON |
| slow_query_log_always_write_time | 10.000000 |
| slow_query_log_file | /data/mysql/13306/tmp/slow.log |
| slow_query_log_timestamp_always | OFF |
| slow_query_log_timestamp_precision | second |
| slow_query_log_use_global_control | |
+------------------------------------+--------------------------------+
6 rows in set (0.01 sec)
+-----------------+----------+
| Variable_name | Value |
+-----------------+----------+
| long_query_time | 0.100000 |
+-----------------+----------+
1 row in set (0.00 sec)
mysql> show global variables like '%general%';
+------------------+--------------------------------+
| Variable_name | Value |
+------------------+--------------------------------+
| general_log | OFF |
| general_log_file | /data/mysql/13306/tmp/file.sql |
+------------------+--------------------------------+
2 rows in set (0.00 sec)
log-queries-not-using-indexes
如果运行的SQL语句没有使用索引，则mysql数据库同样会将这条SQL语句记录到慢查询日志文件中。
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