Netty ChannelManager.tryToOfferChannelToPool discard chunks after offering to pool #834
Description
Hello, the Netty ChannelManager(AHC 1.9.11) seems to have an issue on tryToOfferChannelToPool.
public final void tryToOfferChannelToPool(Channel channel, boolean keepAlive, String partition) {
if (channel.isConnected() && keepAlive && channel.isReadable()) {
LOGGER.debug("Adding key: {} for channel {}", partition, channel);
channelPool.offer(channel, partition);
if (maxConnectionsPerHostEnabled)
channelId2KeyPool.putIfAbsent(channel.getId(), partition);
Channels.setDiscard(channel);
} else {
// not offered
closeChannel(channel);
}
}Looks like channelPool.offer should happen after Channels.setDiscard, otherwise the channel becomes available for selection while the previous request cleanup is still happening. This will cause a "java.util.concurrent.TimeoutException: Request timed out" under certain loads.
This is the snippet I used to reproduce the issue:
final AsyncCompletionHandler<Response> handler = new AsyncCompletionHandler<Response>() {
@Override
public void onThrowable(Throwable t) {
System.out.println(t.toString());
}
@Override
public Response onCompleted(Response response) throws Exception {
return response;
}
};
Request request = httpClient.prepareGet("http://...").build();
for (int i = 0; i < 500; ++i) {
httpClient.executeRequest(request, handler);
}I think the fix should be something similar to:
Channels.setDiscard(channel);
channelPool.offer(channel, partition);instead of :
channelPool.offer(channel, partition);
Channels.setDiscard(channel);