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https://issues.apache.org/jira/browse/TINKERPOP-2268?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16902908#comment-16902908
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Florian Hockmann commented on TINKERPOP-2268:
---------------------------------------------
I would like to understand two things first here: a) Why is there no valid
connection? and b) what causes the timout?
Implementing this fix may help, but I think that it's only a workaround and we
should solve the underlying problem instead.
This might also be related to TINKERPOP-2192 as that problem could lead to dead
connections sitting in the pool.
[~github5775] Can you provide some more information about this problem? When
does it occur? Do you see any exceptions, before or when this happens, either
from Gremlin.Net or on the server side?
> Prevent Connection Failure from Hanging
> ---------------------------------------
>
> Key: TINKERPOP-2268
> URL: https://issues.apache.org/jira/browse/TINKERPOP-2268
> Project: TinkerPop
> Issue Type: Improvement
> Components: dotnet, driver
> Environment: .Net Core
> Reporter: MichaelZ
> Priority: Major
> Original Estimate: 24h
> Remaining Estimate: 24h
>
> When a consumer of the Gremlin.Net client calls to execute a Gremlin query,
> i.e. "SubmitAsync," and there is no valid connection, there will be a costly
> timeout error. I have experienced 30 to 90 second timeouts.
> I was on vacation, so I didn't do this earlier, but I have written a little
> patch that will refresh the connection pool when there is no valid
> connection, and it works flawlessly. This is quick code, and there is a more
> elegant solution, but what I did is to check IsOpen on the first connection
> snapshot, and create a new pool if it was stale. Here is is the code on the
> GremlinClient object:
> {code}
> private ConnectionPool _connectionPool; //{color:#ff0000}used to be
> readonly{color}
> // member variables
> private readonly GremlinServer _gremlinServer = null;
> private readonly GraphSONReader _graphSONReader = null;
> private readonly GraphSONWriter _graphSONWriter = null;
> private readonly string _mimeType = null;
> private readonly ConnectionPoolSettings _connectionPoolSettings = null;
> private readonly Action<ClientWebSocketOptions> _webSocketConfiguration =
> null;
> //
> public GremlinClient(GremlinServer gremlinServer, GraphSONReader
> graphSONReader = null,
> GraphSONWriter graphSONWriter = null, string mimeType = null,
> ConnectionPoolSettings connectionPoolSettings = null,
> Action<ClientWebSocketOptions> webSocketConfiguration = null)
> {
> //
> _gremlinServer = gremlinServer;
> _graphSONReader = graphSONReader;
> _graphSONWriter = graphSONWriter;
> _mimeType = mimeType;
> _connectionPoolSettings = connectionPoolSettings;
> _webSocketConfiguration = webSocketConfiguration;
> //
> {color:#ff0000}NewConnectionPool(){color};
> }
> private void NewConnectionPool()
> {
> var reader = _graphSONReader ?? new GraphSON3Reader();
> var writer = _graphSONWriter ?? new GraphSON3Writer();
> var connectionFactory = new ConnectionFactory(_gremlinServer, reader, writer,
> _mimeType ?? DefaultMimeType, _webSocketConfiguration);
> _connectionPool = new ConnectionPool(connectionFactory,
> _connectionPoolSettings ?? new ConnectionPoolSettings());
> }
> /// <summary>
> /// Provides whether the first available connection snapshot in pool is
> still open.
> /// </summary>
> {color:#ff0000}private{color} bool HasOpenConnection =>
> (bool)_connectionPool?.FirstConnectionSnapshot?.IsOpen;
> /// <inheritdoc />
> public async Task<ResultSet<T>> SubmitAsync<T>(RequestMessage requestMessage)
> {
> if (!HasOpenConnection)
> {
> Debug.WriteLine("=====================================");
> Debug.WriteLine("new connection pool");
> {color:#ff0000}NewConnectionPool(){color};
> }
> using (var connection = await
> _connectionPool.GetAvailableConnectionAsync().ConfigureAwait(false))
> { return await
> connection.SubmitAsync<T>(requestMessage).ConfigureAwait(false); }
> }
> {code}
>
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