/// <summary>
/// Sends the prepare request to all nodes have have an existing open connection. Will not attempt to send the request to hosts that were tried before (successfully or not).
/// </summary>
/// <param name="session"></param>
/// <param name="request"></param>
/// <param name="prepareResult">The result of the prepare request on the first node.</param>
/// <returns></returns>
private async Task SendRequestToAllNodesWithExistingConnections(IInternalSession session, InternalPrepareRequest request, PrepareResult prepareResult)
{
var pools = session.GetPools().ToDictionary(kvp => kvp.Key, kvp => kvp.Value);
if (pools.Count == 0)
{
PrepareHandler.Logger.Warning("Could not prepare query on all hosts because there are no connection pools.");
return;
}
using (var semaphore = new SemaphoreSlim(64, 64))
{
var tasks = new List <Task>(pools.Count);
foreach (var poolKvp in pools)
{
if (poolKvp.Key.Equals(prepareResult.HostAddress))
{
continue;
}
if (prepareResult.TriedHosts.ContainsKey(poolKvp.Key))
{
PrepareHandler.Logger.Warning(
$"An error occured while attempting to prepare query on {{0}}:{Environment.NewLine}{{1}}",
poolKvp.Key,
prepareResult.TriedHosts[poolKvp.Key]);
continue;
}
await semaphore.WaitAsync().ConfigureAwait(false);
tasks.Add(SendSingleRequest(poolKvp, request, semaphore));
}
await Task.WhenAll(tasks).ConfigureAwait(false);
}
}
private async Task <PrepareResult> SendRequestToOneNode(IInternalSession session, IEnumerator <Host> queryPlan, InternalPrepareRequest request)
{
var triedHosts = new Dictionary <IPEndPoint, Exception>();
while (true)
{
// It may throw a NoHostAvailableException which we should yield to the caller
var connection = await GetNextConnection(session, queryPlan, triedHosts).ConfigureAwait(false);
try
{
var result = await connection.Send(request).ConfigureAwait(false);
return(new PrepareResult
{
PreparedStatement = await GetPreparedStatement(result, request, connection.Keyspace, session.Cluster).ConfigureAwait(false),
TriedHosts = triedHosts,
HostAddress = connection.Address
});
}
catch (Exception ex) when(PrepareHandler.CanBeRetried(ex))
{
triedHosts[connection.Address] = ex;
}
}
}
