7
是否有解释这些状态的地方？mysql profiler“发送数据”
http://dev.mysql.com/tech-resources/articles/using-new-query-profiler.html
我的具体问题是关于这个查询：
select count(*)
from 135_5m.record_updates u, 135_5m.records r
where r.record_id = u.record_id and
(u.date_updated > null or null is null) and
u.date_updated <= '2011-01-03';
它返回一个数字 - 4053904.那么，为什么大多数的时间花费在“发送数据”？它只是名字不好吗？当然，“发送数据”不仅仅是发送数据？
+--------------------------------+-----------+-------+
| Status | Duration | Swaps |
+--------------------------------+-----------+-------+
| starting | 0.000224 | 0 |
| checking query cache for query | 0.000188 | 0 |
| checking permissions | 0.000012 | 0 |
| checking permissions | 0.000017 | 0 |
| Opening tables | 0.000036 | 0 |
| System lock | 0.000015 | 0 |
| Table lock | 0.000067 | 0 |
| init | 0.000105 | 0 |
| optimizing | 0.000052 | 0 |
| statistics | 0.000254 | 0 |
| preparing | 0.000061 | 0 |
| executing | 0.000017 | 0 |
| Sending data | 32.079549 | 0 |
| end | 0.000036 | 0 |
| query end | 0.000012 | 0 |
| freeing items | 0.000089 | 0 |
| storing result in query cache | 0.000022 | 0 |
| logging slow query | 0.000008 | 0 |
| logging slow query | 0.000008 | 0 |
| cleaning up | 0.000011 | 0 |
+--------------------------------+-----------+-------+
题外话，但什么是该位的目的的majrity时间'u.date_updated>空或null为null'？肯定它总是真的？ – 2010-09-07 13:00:17
该查询最初是java代码中的预备状态。我取代了？在我的代码中使用实际值来测试性能。 – andersonbd1 2010-09-07 14:33:21