MySQL Bugs: #64012: CommandText property set method performance improvement

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:	Windows (7 64-bit)
Assigned to:	Fernando Gonzalez.Sanchez	CPU Architecture:	Any

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.

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.

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.