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https://issues.apache.org/jira/browse/IGNITE-12032?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16931117#comment-16931117
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Lev Agafonov commented on IGNITE-12032:
---------------------------------------
[~isapego], [~dmagda]
Hello, Igor! Yep, I'm new to Ignite and started contribute recently.
Let me make summary, I've already investigated on this ticket:
# The root cause of this error is closing +network+ connection from user
application side, using thin client without notifying server about closing
+database+ connection itself. It's similar to finishing work with your personal
computer by immediate disconnecting plug from socket :). In this case server
doesn't expect that network connection is closed and we got WARN message from
Ignite on server side: "_Closing NIO session because of unhandled exception_"
and the IOException from Java itself.
# The right way of finishing work with database connection is:
resultset.close(); statement.close(), connection.close(). In case of this issue
- `connection.close()` from user application side is enough to get things good.
# As a solution I'd like to make WARN message (in class GridNioServer) more
user-friendly, giving a clue for the most often reason what goes wrong and how
it can be fixed, by changing current WARN message from "_Closing NIO session
because of unhandled exception_" to "Client connection lost, make sure
connection.close() called before closing database connection". If everything
clear, and you don't object - I'd like to make a PR.
Thank you!
> Server node prints exception when ODBC driver disconnects
> ---------------------------------------------------------
>
> Key: IGNITE-12032
> URL: https://issues.apache.org/jira/browse/IGNITE-12032
> Project: Ignite
> Issue Type: Bug
> Components: thin client
> Affects Versions: 2.7.5
> Reporter: Evgenii Zhuravlev
> Assignee: Lev Agafonov
> Priority: Minor
> Labels: newbie, usability
> Fix For: 2.8
>
>
> Whenever a process using ODBC clients is finished, it's printing in the
> node logs this exception:
> {code:java}
> *[07:45:19,559][SEVERE][grid-nio-worker-client-listener-1-#30][ClientListenerProcessor]
>
> Failed to process selector key [s
> es=GridSelectorNioSessionImpl [worker=ByteBufferNioClientWorker
> [readBuf=java.nio.HeapByteBuffer[pos=0 lim=8192 cap=8192
> ], super=AbstractNioClientWorker [idx=1, bytesRcvd=0, bytesSent=0,
> bytesRcvd0=0, bytesSent0=0, select=true, super=GridWo
> rker [name=grid-nio-worker-client-listener-1, igniteInstanceName=null,
> finished=false, heartbeatTs=1564289118230, hashCo
> de=1829856117, interrupted=false,
> runner=grid-nio-worker-client-listener-1-#30]]], writeBuf=null,
> readBuf=null, inRecove
> ry=null, outRecovery=null, super=GridNioSessionImpl
> [locAddr=/0:0:0:0:0:0:0:1:10800, rmtAddr=/0:0:0:0:0:0:0:1:63697, cre
> ateTime=1564289116225, closeTime=0, bytesSent=1346, bytesRcvd=588,
> bytesSent0=0, bytesRcvd0=0, sndSchedTime=156428911623
> 5, lastSndTime=1564289116235, lastRcvTime=1564289116235, readsPaused=false,
> filterChain=FilterChain[filters=[GridNioAsyn
> cNotifyFilter, GridNioCodecFilter [parser=ClientListenerBufferedParser,
> directMode=false]], accepted=true, markedForClos
> e=false]]]
> java.io.IOException: An existing connection was forcibly closed by the
> remote host
> at sun.nio.ch.SocketDispatcher.read0(Native Method)
> at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:43)
> at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223)
> at sun.nio.ch.IOUtil.read(IOUtil.java:197)
> at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:380)
> at
> org.apache.ignite.internal.util.nio.GridNioServer$ByteBufferNioClientWorker.processRead(GridNioServer.java:11
>
> 04)
> at
> org.apache.ignite.internal.util.nio.GridNioServer$AbstractNioClientWorker.processSelectedKeysOptimized(GridNi
>
> oServer.java:2389)
> at
> org.apache.ignite.internal.util.nio.GridNioServer$AbstractNioClientWorker.bodyInternal(GridNioServer.java:215
>
> 6)
> at
> org.apache.ignite.internal.util.nio.GridNioServer$AbstractNioClientWorker.body(GridNioServer.java:1797)
>
> at
> org.apache.ignite.internal.util.worker.GridWorker.run(GridWorker.java:120)
> at java.lang.Thread.run(Thread.java:748)*
> {code}
> It's absolutely normal behavior when ODBC client disconnects from the node,
> so, we shouldn't print exception in the log. We should replace it with
> something like INFO message about ODBC client disconnection.
> Thread from user list:
> http://apache-ignite-users.70518.x6.nabble.com/exceptions-in-Ignite-node-when-a-thin-client-process-ends-td28970.html
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