Update records in a loop performance in c# and sql

Question

I need to update 100 records in database from my application in C#.

I have used a foreach statement and called a stored procedure to update each records like this:

foreach (var record in recordList)
{  
    dbWatch.Start();
    DbService.UpdateRecord(Id, ProcessDate, MessageID, task.Result.Email.TryTimes);
    dbWatch.Stop();
    LogMessage(string.Format("Single database row update toke:{0}",dbWatch.Elapsed));
}

Everything is working fine except that when its starts, it's taking about 00:00:00.00123343 to update each record, but as its going to update more and more, it takes more and more. After almost 1000 records it take about 00:00:04 seconds to update each records.

I'm wondering why it's like that?

Answer 1

I assume this is just an incorrect measurement. Your loop does not restart the StopWatch , it just starts and stops it consecutively. So Elapsed will always increase.

If you want to measure the entire time:

dbWatch.Start();
foreach (var record in recordList)
{  
    DbService.UpdateRecord(Id, ProcessDate, MessageID, task.Result.Email.TryTimes);
}
dbWatch.Stop();
LogMessage(string.Format("All updates took:{0}",dbWatch.Elapsed));

If you want to measure the time for each iteration use StopWatch.Restart :

foreach (var record in recordList)
{  
    dbWatch.Restart();
    DbService.UpdateRecord(Id, ProcessDate, MessageID, task.Result.Email.TryTimes);
    dbWatch.Stop();
    LogMessage(string.Format("Single database row update took:{0}",dbWatch.Elapsed));
}

Answer 2

You would have to call dbWatch.Reset() at the end of the loop or Restart() at the beginning if you want to measure the time of each Update. I assume its a System.Diagnostics.Stopwatch . See MSDN - Stopwatch .