MySQL Bugs: #38950: Quan shows no Execution time for "fast" queries on Windows

Bug #38950	Quan shows no Execution time for "fast" queries on Windows
Submitted:	21 Aug 2008 23:04	Modified:	3 Nov 16:21
Reporter:	Bill Weber
Status:	Verified
Category:	Monitoring: Agent	Severity:	S3 (Non-critical)
Version:	2.0.0.7032	OS:	Microsoft Windows
Assigned to:	Kay Roepke	Target Version:	2.01 maint release

Description:
On Windows, fast queries show as taking no time to execute on the Query Analysis tab
(Execution = 0.000). Note, the reason for this is that glib uses
GetSystemTimeAsFileTime() which has a 10ms accuracy.

How to repeat:
- install and start dashboard
- install and start an agent on Windows with query analysis turned on
- run some small/fast queries through the proxy
- go to Query Analysis page on dashboard
| notice Execution time = 0.000

Suggested fix:
 use something like this for windows:
 LARGE_INTEGER freq;
 LARGE_INTEGER startTime, endTime;
 LARGE_INTEGER elapsedTime, elapsedMilliseconds;
 QueryPerformanceFrequency(&freq);
 QueryPerformanceCounter(&startTime);
 / run code here
 QueryPerformanceCounter(&endTime);
 elapsedTime = endTime - startTime;
 elapsedMilliseconds = (1000 * elapsedTime) / freq;

A note has been added to the documentation in the QA chapter on this issue.