slow_launch_time和long_query_time

1.slow_launch_time

If creating a thread takes longer than this many seconds, the server increments the Slow_launch_threadsstatus variable.

如果創建線程需要比slow_launch_time更多的時間，服務器會增加 Slow_launch_threads的狀態變量。

 Slow_launch_threads

The number of threads that have taken more than slow_launch_time seconds to create.

創建時間超過slow_launch_time的線程個數。

2.long_query_time

If a query takes longer than this many seconds, the server increments the Slow_queries status variable. If the slow query log is enabled, the query is logged to the slow query log file. This value is measured in real time, not CPU time, so a query that is under the threshold on a lightly loaded system might be above the threshold on a heavily loaded one. The minimum and default values of long_query_time are 0 and 10, respectively. The value can be specified to a resolution of microseconds. For logging to a file, times are written including the microseconds part. For logging to tables, only integer times are written; the microseconds part is ignored. 

如果查詢需要比long_query_time更多的時間，服務器會增加slow_queries的狀態變量。如果啟用了慢查詢日志，則查詢將記錄到慢查詢日志文件中。此值是實時測量的，而不是中央處理器的時間，所以一個在輕負載系統的閾值下的查詢可能會高于重負載的系統的閾值。最小值和默認值long_query_time分別為0和10。該值可以精確到微秒。如果記錄到文件中，時間包括微秒部分。如果記錄到表，只有整數部分；微秒部分被忽略。

Slow_queries

The number of queries that have taken more than long_query_time seconds. This counter increments regardless of whether the slow query log is enabled.

查詢時間超過long_query_time 的查詢數目，這個數值的增加與是否啟動慢查詢日志無關。

總結：從上面的內容可以看出，slow_launch_time和long_query_time雖然模樣差不多，但是關系卻沒那么近。