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.NET Forum / .NET Framework / Interop / April 2004slow reading of eventlog
I need to read the entire eventlog and parse it. The application uses vb.net and the EventLog object. The problem i'm having is that it can take less then a second up to 15 seconds to read all entries in the eventlog. I used Perfmon and found the following two counters that were used heavily .NET CLR Security Total Runtime Check .NET CLR Interop # of marshallin I have written some sample code that shows my problem Module Module '<System.Security.SuppressUnmanagedCodeSecurity()> Sub Main( 'Dim evl As New EventLog("System" Dim evl As New EventLog("Application" Dim str As Strin Dim startTime, endTime As Dat str = "No entries: " & evl.Entries.Coun Debug.WriteLine(str Console.WriteLine(str For x As Integer = 0 To startTime = No For Each entry As EventLogEntry In evl.Entrie str = entry.UserName & entry.Source & entry.MachineName & entry.Category & entry.CategoryNumber & entry.EntryType & entry.EventID & entry.Index & entry.TimeGenerated & entry.Messag Nex endTime = No str = "Started: " & startTime.ToString("HH:mm:ss.ffff") & vbCrLf & "Ended: " & endTime.ToString("HH:mm:ss.ffff" Debug.WriteLine(str Console.WriteLine(str Nex End Su End Modul When i run it on a P4 machine (3GHz and 2G ram) i get the following results No entries: 170 Started: 12:04:34.875 Ended: 12:04:38.890 No entries: 193 Started: 12:05:37.937 Ended: 12:05:39.859 Since the application i'm writing is a graphical one i don't want any hangings Any ideas how i can trim the system or change the code to make it run faster Hi, Two suggestions. 1) This cuts the run time in half on my system. It is quicker to create a new string than destroy and create a old one. For Each entry As EventLogEntry In evl.Entries Dim strEntry As String strEntry = String.Format("{0} {1} {2} {3} {4} {5} {6} {7} {8} {9}", entry.UserName, entry.Source, entry.MachineName, _ entry.Category, entry.CategoryNumber, entry.EntryType, _ entry.EventID, entry.Index, entry.TimeGenerated, entry.Message) Next No entries: 2055 Started: 06:44:13.2701 Ended: 06:44:16.7451 2) If you are worried about performance process the event log in a seperate thread. Ken ----------------- >I need to read the entire eventlog and parse it. The application uses >vb.net and the EventLog object. The problem i'm having is that it can take [quoted text clipped - 58 lines] > Any ideas how i can trim the system or change the code to make it run > faster. thanks for the responses this was just an example. in the real application the data is displayed in a ListView, but i still have to read all entries and make a decision about what to display. If i run this example against my Security log i get these numbers No entries: Started: 14:22:13.515 Ended: 14:22:15.765 It takes ~two seconds to read one(!!) entry. Hi Zorro, As an alternative for Ken For Each entry As EventLogEntry In evl.Entries dim sb as new system.text.stringbuilder(entry.UserName) sb.append(entry.Source) sb.append(etc.) do it really one by one so also sb.append("Started: ") sb.append(Startime.toString) at the end str = sb.toString I am curious which one is the fastest? Cor wellwell a post of me long time ago: after the very small & vs string.format discussion I did some speed tests... loop of 1.000.000 concatenations of 5 public string variables in a class gave following results: result = a & b & c & d & e +/- 420ms result = a result &= b result &= c result &= d result &= e +/- 370ms dim result as new StringBuilder() result.Append(a) result.Append(b) result.Append(c) result.Append(d) result.Append(e) new StringBuilder in each loop: +/- 730ms new StringBuilder outside + result.length=0 in each loop: +/- 690ms result = String.Format("{0}{1}{2}{3}{4}", a, b, c, d, e) +/- 1540ms so in my opinion, only use string.format to do real formatting :-) the difference between the first 2 seems strange to me is this a compiler problem? oh yes, everything was ran in debug mode in visual studio 2003... dominique Hi Dominique, I tested it and the test is bellow. With short strings I had almost the same results as you. Although using the SB was the fastest while the concatanation of short strings in line was almost the same. What was also slightly different with me was that the creation of the SB inside the loop the time was twice as much as with setting the length to 0, (that test with new SB is not included). However when the strings become longer, what is in the end of the test, I had to bring the test down to 1000 loops when I did not wanted to wait to long using something other than the stringbuilder. Maybe you can have a look at it and when I did test something wrong tell me? Cor Module Teststrings Public Sub main() Dim arl As New ArrayList arl.Add("This is string one") arl.Add("This is string two") arl.Add("This is string three") arl.Add("This is string four") arl.Add("This is string five") arl.Add("This is string six") arl.Add("This is string seven") arl.Add("This is string eight") arl.Add("This is string nine") arl.Add("This is string ten") Dim str As String Dim start As Integer = Environment.TickCount Dim sb As New System.Text.StringBuilder("") For i As Integer = 0 To 100000 sb.Length = 0 sb.Append(arl(0).ToString) sb.Append(arl(1).ToString) sb.Append(arl(2).ToString) sb.Append(arl(3).ToString) sb.Append(arl(4).ToString) sb.Append(arl(5).ToString) sb.Append(arl(6).ToString) sb.Append(arl(7).ToString) sb.Append(arl(8).ToString) sb.Append(arl(9).ToString) Next str = sb.ToString MessageBox.Show("Short strings with stringbuilder: " & _ (Environment.TickCount - start).ToString) start = Environment.TickCount For i As Integer = 0 To 100000 str = arl(0).ToString & arl(1).ToString & arl(3).ToString _ & arl(4).ToString & arl(5).ToString & _ arl(6).ToString & arl(7).ToString & arl(8).ToString & arl(9).ToString Next MessageBox.Show("Short strings with concat in row: " & _ (Environment.TickCount - start).ToString) start = Environment.TickCount For i As Integer = 0 To 100000 str = arl(0).ToString str &= arl(1).ToString str &= arl(2).ToString str &= arl(3).ToString str &= arl(4).ToString str &= arl(5).ToString str &= arl(6).ToString str &= arl(7).ToString str &= arl(8).ToString str &= arl(9).ToString Next MessageBox.Show("Short strings with concat row by row: " _ & (Environment.TickCount - start).ToString) start = Environment.TickCount For i As Integer = 0 To 100000 str = str.Format("{0},{1},{2},{3},{4},{5},{6},{7},{8},{9}", arl(0).ToString, _ arl(1).ToString, arl(2).ToString, arl(3).ToString, arl(4).ToString, arl(5).ToString, _ arl(6).ToString, arl(7).ToString, arl(8).ToString, arl(9).ToString) Next MessageBox.Show("Short strings with format :" & _ (Environment.TickCount - start).ToString) 'Concetanation start = Environment.TickCount sb.Length = 0 For i As Integer = 0 To 1000 sb.Append(arl(0).ToString) sb.Append(arl(1).ToString) sb.Append(arl(2).ToString) sb.Append(arl(3).ToString) sb.Append(arl(4).ToString) sb.Append(arl(5).ToString) sb.Append(arl(6).ToString) sb.Append(arl(7).ToString) sb.Append(arl(8).ToString) sb.Append(arl(9).ToString) Next str = sb.ToString MessageBox.Show("Building a long string with sb : " & _ (Environment.TickCount - start).ToString) str = "" start = Environment.TickCount For i As Integer = 0 To 1000 str &= arl(0).ToString & arl(1).ToString & _ arl(3).ToString & arl(4).ToString & arl(5).ToString & _ arl(6).ToString & arl(7).ToString & arl(8).ToString & arl(9).ToString Next MessageBox.Show("Building a long string with concat in a row : " _ & (Environment.TickCount - start).ToString) start = Environment.TickCount str = "" For i As Integer = 0 To 1000 str &= arl(0).ToString str &= arl(1).ToString str &= arl(2).ToString str &= arl(3).ToString str &= arl(4).ToString str &= arl(5).ToString str &= arl(6).ToString str &= arl(7).ToString str &= arl(8).ToString str &= arl(9).ToString Next MessageBox.Show("Building a long string with concat : " _ & (Environment.TickCount - start).ToString) start = Environment.TickCount str = "" For i As Integer = 0 To 1000 str &= str.Format("{0},{1},{2},{3},{4},{5},{6},{7},{8},{9}", _ arl(0).ToString, arl(1).ToString, arl(2).ToString, _ arl(3).ToString, arl(4).ToString, arl(5).ToString, _ arl(6).ToString, arl(7).ToString, arl(8).ToString, arl(9).ToString) Next MessageBox.Show("Building a long string with format : " _ & (Environment.TickCount - start).ToString) End Sub End Module Free MagazinesGet these publications absolutely FREE for up to 12 months. 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