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https://issues.apache.org/jira/browse/LOG4NET-605?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Ralph Goers updated LOG4NET-605:
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LOG4NET is now dormant.
> AdoNetAppenderIssue Multithreaded Application Freeze
> ----------------------------------------------------
>
> Key: LOG4NET-605
> URL: https://issues.apache.org/jira/browse/LOG4NET-605
> Project: Log4net
> Issue Type: Bug
> Components: Core
> Affects Versions: 2.0.8
> Environment: Windows, MS SQL Server 2016
> Reporter: Sebastian Morgenbesser
> Priority: Major
> Attachments: log4etbugshowcase_visual_studio_project.zip
>
>
> I recently noticed a strange issue with log4net and the AdoNetAppender and it
> would be nice if anyone could comment on this.
> Its quite an Edge Case I know but the implication is that the Application
> will freeze and no Exception is thrown which is kind of scary.
> I have made a small example C# project to illustrate the issue which I can
> provide, but first I want to explain the issue.
> The scenario is like this:
> * Visual Studio C# Console Application. Log4net (latest version) embedded as
> dll, MS SQL Server 2016 (but I guess this doesn't matter), .NET Framework >
> 4.5
> * The Application starts and the Logger is initialized (containing a
> AdoNetAppender pointing to an existing Database on MS SQL Server - localhost)
> ** The code is something like this:
> **
> * After that happened, the Application is going to DROP the Database
> containing the Table that log4net will log to and recreates the database with
> all tables
> ** This happens because every time the console starts the Log-Database
> should be empty (I know there are other ways like truncate oder Drop Table
> but lets stay with me to understand the problem)
> * So at this point the Database containing the Log Table has been recreated.
> * Now the Application starts a number Threads (in my example 64, but I guess
> it works with less) and waits for them to finish
> * In the Do() Method of the Thread, the thread simply tries to log an Error
> Message to the previously initialized logger
> * The Result is that the Application freezes and will never return (0% CPU).
> Also no log messages arrive in the database.
> * I am guessing there is some kind of deadlock situation inside log4net if
> multiple threads try to "initialize" the database connection to the recreated
> database again but in detail I have no idea what happens.
> * No exception is thrown, the threads just never finish there Do() Method
> So if I skip the part where I Recreate the database (with DROP und CREATE
> Database), then it works.
> Also if put a log statement after the recreation of the database but BEFORE
> the multithreaded part starts, it also works.
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