[GitHub] [lucenenet] NightOwl888 opened a new issue #526: Task: Replace Thread.Interrupt() with a safer shutdown mechanism

[GitBox <gi...@apache.org>]

NightOwl888 opened a new issue #526:
URL: https://github.com/apache/lucenenet/issues/526


   In #525, we discovered that using `Thread.Interrupt()` is not practical in .NET because it may throw on any `lock` statement that has contention on it. This makes it too unpredictable to use in conjunction with a transaction (i.e. `IndexWriter.Commit()`) and we will need to redesign it so transactions are guaranteed to succeed.
   
   Some preliminary research:
   
   1. https://stackoverflow.com/a/3632642
   2. https://jonskeet.uk/csharp/threads/abort.html
   
   2 of the contenders are already in use throughout the project - using `ManualResetEvent` and using a `bool` switch. Lucene makes it pretty clear where it is safe to assume we are in a consistent state (wherever we see `IsInterruptedException()` in a catch block and rethrown as `Lucene.Net.Util.ThreadInterruptedException`).
   
   There are just a few places in Lucene where `Interrupt()` is called:
   
   - [ConcurrentMergeScheduler](https://github.com/apache/lucene/blob/releases/lucene-solr/4.8.0/lucene/core/src/java/org/apache/lucene/index/ConcurrentMergeScheduler.java#L292)
   - [IndexWriter](https://github.com/apache/lucene/blob/releases/lucene-solr/4.8.0/lucene/core/src/java/org/apache/lucene/index/IndexWriter.java#L1080)
   - [ControlledRealTimeReopenThread](https://github.com/apache/lucene/blob/releases/lucene-solr/4.8.0/lucene/core/src/java/org/apache/lucene/search/ControlledRealTimeReopenThread.java#L228)
   - [TestIndexWriter (1)](https://github.com/apache/lucene/blob/releases/lucene-solr/4.8.0/lucene/core/src/test/org/apache/lucene/index/TestIndexWriter.java#L1212)
   - [TestIndexWriter (2)](https://github.com/apache/lucene/blob/releases/lucene-solr/4.8.0/lucene/core/src/test/org/apache/lucene/index/TestIndexWriter.java#L1249)
   - [TestControlledRealTimeReopenThread (1)](https://github.com/apache/lucene/blob/releases/lucene-solr/4.8.0/lucene/core/src/test/org/apache/lucene/search/TestControlledRealTimeReopenThread.java#L359)
   - [TestControlledRealTimeReopenThread (2)](https://github.com/apache/lucene/blob/releases/lucene-solr/4.8.0/lucene/core/src/test/org/apache/lucene/search/TestControlledRealTimeReopenThread.java#L369)
   - [ReplicationClient (1)](https://github.com/apache/lucene/blob/releases/lucene-solr/4.8.0/lucene/replicator/src/java/org/apache/lucene/replicator/ReplicationClient.java#L97)
   - [ReplicationClient (2)](https://github.com/apache/lucene/blob/releases/lucene-solr/4.8.0/lucene/replicator/src/java/org/apache/lucene/replicator/ReplicationClient.java#L367)
   
   And here is a list of all of the locations where `InterruptException` is handled:
   
   [InterruptedException Investigation Table.xlsx](https://github.com/apache/lucenenet/files/7360268/InterruptedException.Investigation.Table.xlsx)
   
   A logical approach would be to create a subclass of [`J2N.Threading.ThreadJob`](https://github.com/NightOwl888/J2N/blob/3d3c7211a39395c00aa3dfd1cdf9c01501391d87/src/J2N/Threading/ThreadJob.cs) and add the boilerplate code for shutting down the thread, then swap the base class throughout Lucene along with the code to call the new shutdown mechanism.
   


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[GitHub] [lucenenet] NightOwl888 closed issue #526: Task: Change documentation about Thread.Interrupt() to indicate this is not safe to use with Lucene.NET

[GitBox <gi...@apache.org>]

NightOwl888 closed issue #526:
URL: https://github.com/apache/lucenenet/issues/526


   


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