Bug #64012 CommandText property set method performance improvement
Submitted: 12 Jan 2012 14:34 Modified: 8 Mar 2012 19:22
Reporter: Kim Christensen Email Updates:
Status: Closed Impact on me:
None 
Category:Connector / NET Severity:S5 (Performance)
Version:6.4.4.0 OS:Microsoft Windows (7 64-bit)
Assigned to: Fernando Gonzalez.Sanchez CPU Architecture:Any

[12 Jan 2012 14:34] Kim Christensen
Description:
Performance when setting the CommandText property on the MySqlCommand class, can be improved by factor 100, on a very large number of queries.

How to repeat:
const string Test = "hdasjkhdasjkhdasdhjsdadasddjkasklædaklæsdlækasdkklæasdklæasd  fdfsdfsd dsa8() default";
Stopwatch stopwatch = new Stopwatch();
stopwatch.Start();
for (int i = 0; i < 10000000; i++)
{
	Test.EndsWith("default", StringComparison.Ordinal);
}
stopwatch.Stop();

Console.WriteLine("Took " + stopwatch.Elapsed);

stopwatch.Reset();
stopwatch.Start();
for (int i = 0; i < 10000000; i++)
{
	Test.EndsWith("default");
}
stopwatch.Stop();

Console.WriteLine("Took " + stopwatch.Elapsed);

My output are:
Took 00:00:00.2348015
Took 00:00:20.3238133

Suggested fix:
This can be done by changing the line 131 in MySqlCommand.cs:
if (cmdText != null && cmdText.EndsWith("DEFAULT VALUES"))
with the following:
if (cmdText != null && cmdText.EndsWith("DEFAULT VALUES", StringComparison.Ordinal))

The reason for this is that EndsWith by default compares using the current culture, which apparently are very slow compared to StringComparison.Ordinal.
[8 Mar 2012 19:22] Fernando Gonzalez.Sanchez
Thank you for your bug report. This issue has already been fixed in the latest released version of that product, which you can download at

  http://www.mysql.com/downloads/

This has been fixed and released in 6.5.4 and will be released in 6.3.9 & 6.4.5.
[12 Apr 2012 1:37] John Russell
Added to changelog for 6.3.9, 6.4.5, 6.5.3: 

The performance when setting the CommandText property on the
MySqlCommand class was improved by enhancing the efficiency of a
string comparison operation.