Bug: Ensure FileStreamTask cannot compromise shared channel proxy for system table when interrupted
Status: Resolved
Priority: Normal
Resolution: Fixed
Created: 25/May/22 17:42
Resolved: 02/Jun/22 17:27

This is very similar to what we fixed in CASSANDRA-17466 , just in a different part of the repair/streaming machine.

{{NettyStreamingMessageSender}} is responsible for dispatching {{FileStreamTask}} on an executor it manages to stream files to its peers. When the sender is closed for any reason, like perhaps a peer blowing up while deserializing the stream, the executor it manages is shut down w/ interruption (i.e. {{shutdownNow()}}). This is problematic if we happen to have not gotten very far along in {{FileStreamTask#run()}}. If we're just about to call {{getOrCreateChannel()}}, which reads from the {{peers_v2}} system table, the {{ChannelProxy}} read will throw a {{ClosedByInterruptedException}} and the proxy will be useless. The twist is that, since CASSANDRA-15666, this exception has essentially been swallowed by {{FileStreamTask}}'s exception handling. So we don't see a {{ClosedByInterruptedException}} in the logs, but we do have things like this pop up when anything else tries to hit the peers table:

{noformat}
ERROR 2022-05-19T21:49:23,218 [AntiEntropyStage:1] org.apache.cassandra.service.CassandraDaemon:601 - Exception in thread Thread[AntiEntropyStage:1,5,main]
java.lang.RuntimeException: FSReadError in .../data/system/peers_v2-c4325fbb8e5e3bafbd070f9250ed818e/system-peers_v2-nb-101-big-Data.db
        at org.apache.cassandra.net.InboundSink.accept(InboundSink.java:108) 
        at org.apache.cassandra.net.InboundSink.accept(InboundSink.java:45)
        at org.apache.cassandra.net.InboundMessageHandler$ProcessMessage.run(InboundMessageHandler.java:433)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) 
        at java.util.concurrent.FutureTask.run(FutureTask.java:264)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) [netty-all-4.1.58.Final.jar:4.1.58.Final]
        at java.lang.Thread.run(Thread.java:834)
Caused by: org.apache.cassandra.io.FSReadError: java.nio.channels.ClosedChannelException
        at org.apache.cassandra.io.util.ChannelProxy.read(ChannelProxy.java:143) 
        at org.apache.cassandra.io.util.CompressedChunkReader$Standard.readChunk(CompressedChunkReader.java:115) 
        at org.apache.cassandra.io.util.BufferManagingRebufferer.rebuffer(BufferManagingRebufferer.java:79) 
        at org.apache.cassandra.io.util.RandomAccessReader.reBufferAt(RandomAccessReader.java:68) 
        at org.apache.cassandra.io.util.RandomAccessReader.seek(RandomAccessReader.java:210) 
        at org.apache.cassandra.io.util.FileHandle.createReader(FileHandle.java:151) 
{noformat}

...and...

{noformat}
ERROR 2022-05-19T22:06:20,175 [CompactionExecutor:12] org.apache.cassandra.service.CassandraDaemon:601 - Exception in thread Thread[CompactionExecutor:12,1,main]
org.apache.cassandra.io.FSReadError: java.nio.channels.ClosedChannelException
        at org.apache.cassandra.io.util.ChannelProxy.read(ChannelProxy.java:143) 
        at org.apache.cassandra.io.util.CompressedChunkReader$Standard.readChunk(CompressedChunkReader.java:115) 
        at org.apache.cassandra.io.util.BufferManagingRebufferer.rebuffer(BufferManagingRebufferer.java:79) 
        at org.apache.cassandra.io.util.RandomAccessReader.reBufferAt(RandomAccessReader.java:68) 
        at org.apache.cassandra.io.util.RandomAccessReader.seek(RandomAccessReader.java:210) 
        at org.apache.cassandra.io.sstable.format.big.BigTableScanner.seekToCurrentRangeStart(BigTableScanner.java:196) 
        at org.apache.cassandra.io.sstable.format.big.BigTableScanner.access$400(BigTableScanner.java:52) 
        at org.apache.cassandra.io.sstable.format.big.BigTableScanner$KeyScanningIterator.computeNext(BigTableScanner.java:305) 
        at org.apache.cassandra.io.sstable.format.big.BigTableScanner$KeyScanningIterator.computeNext(BigTableScanner.java:282) 
        at org.apache.cassandra.utils.AbstractIterator.hasNext(AbstractIterator.java:46) 
        at org.apache.cassandra.io.sstable.format.big.BigTableScanner.hasNext(BigTableScanner.java:261) 
{noformat}

...which obviously get us into trouble w/ the disk failure policy.

The fix proposed here is just to get the peers table read out of the thread that can be interrupted. Specifically, {{NettyStreamingMessageSender}} materializes a {{connectTo}} address at stream task creation time. This seemed a better option than making shutdown non-interrupting, since that would mean changing how the actual file streaming responds to shutdown.