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Stefan Bodewig commented on LOG4NET-212: ---------------------------------------- The same is true fro AppenderSkeleton.RenderLoggingEvent(LoggingEvent). I agree that proper locking would impact performance more than simply creating new StringWriters as needed. I'll set up some simplistic multi-threaded test scenario. > Threading bug in the PatternConverter.cs > ---------------------------------------- > > Key: LOG4NET-212 > URL: https://issues.apache.org/jira/browse/LOG4NET-212 > Project: Log4net > Issue Type: Bug > Components: Core > Affects Versions: 1.2.10 > Environment: Windows, .NET 2.0 / 3.5, C# > Reporter: Jerry van Leeuwen > Fix For: 1.2.11 > > > Every once in a while I get the following exception: > System.ArgumentOutOfRangeException: Index and length must refer to a > location within the string. > Parameter name: length > at System.String.InternalSubStringWithChecks(Int32 startIndex, Int32 > length, Boolean fAlwaysCopy) > at System.Text.StringBuilder.ToString(Int32 startIndex, Int32 length) > at log4net.Util.PatternConverter.Format(TextWriter writer, Object > state) in xxx\Log4Net\src\Util\PatternConverter.cs:line 187 > at log4net.Layout.PatternLayout.Format(TextWriter writer, LoggingEvent > loggingEvent) in xxx\Log4Net\src\Layout\PatternLayout.cs:line 1009 > at > Nemmco.Common.Initialization.Internal.NemLoggingAppender.Execute(DateTime > lastTrigger, DateTime currentTrigger) in > xxxInitialization\Internal\InitializationLogging.cs:line 765 > --snip-- > From my own investigation it looks like the problem occurs because the shared > string buffer (from the m_formatWriter.GetStringBuilder() call) may end up in > a state where its size is adjusted differently on separate threads, causing > one thread to over-estimate the available length. > I wonder if the re-use of a StringWriter / StringBuilder in this scenario > actually outweighs the threading implications? The simplest fix would be to > replace use of m_formatWriter with use of a local StringWriter / > StringBuilder. -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira