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Posted to issues-all@impala.apache.org by "Michael Ho (JIRA)" <ji...@apache.org> on 2018/09/18 22:54:00 UTC
[jira] [Commented] (IMPALA-7565) Extends TAcceptQueueServer
connection_setup_pool to be multi-threaded
[ https://issues.apache.org/jira/browse/IMPALA-7565?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16619839#comment-16619839 ]
Michael Ho commented on IMPALA-7565:
------------------------------------
Upgrading to blocker as this is a pretty bad behavior for Impala to have.
> Extends TAcceptQueueServer connection_setup_pool to be multi-threaded
> ---------------------------------------------------------------------
>
> Key: IMPALA-7565
> URL: https://issues.apache.org/jira/browse/IMPALA-7565
> Project: IMPALA
> Issue Type: Improvement
> Components: Clients, Distributed Exec
> Affects Versions: Impala 2.11.0, Impala 3.0, Impala 2.12.0
> Reporter: Michael Ho
> Priority: Blocker
>
> In {{TAcceptQueueServer.cpp}}, we currently have one thread in the {{connection_setup_pool}} for handling connection establishment.
> {noformat}
> // Only using one thread here is sufficient for performance, and it avoids potential
> // thread safety issues with the thrift code called in SetupConnection.
> constexpr int CONNECTION_SETUP_POOL_SIZE = 1;
> // New - this is the thread pool used to process the internal accept queue.
> ThreadPool<shared_ptr<TTransport>> connection_setup_pool("setup-server", "setup-worker",
> CONNECTION_SETUP_POOL_SIZE, FLAGS_accepted_cnxn_queue_depth,
> [this](int tid, const shared_ptr<TTransport>& item) {
> this->SetupConnection(item);
> });
> {noformat}
> While that makes the code easier to reason about, it also makes Impala less robust in case a client intentionally or unintentionally freezes during connection establishment. For instance, one can telnet to the beeswax or HS2 port of Impala (e.g. telnet localhost:21000) and then leave the telnet session open. In a secure cluster with TLS enabled, Impalad will be stuck in the SSL handshake. Other clients trying to connect to that port (e.g. Impala shell) will hang forever.
> {noformat}
> Thread 551 (Thread 0x7fddde563700 (LWP 166354)):
> #0 0x0000003ce2a0e82d in read () from /lib64/libpthread.so.0
> #1 0x0000003ce56dea71 in ?? () from /usr/lib64/libcrypto.so.10
> #2 0x0000003ce56dcdc9 in BIO_read () from /usr/lib64/libcrypto.so.10
> #3 0x0000003ce9a31873 in ssl23_read_bytes () from /usr/lib64/libssl.so.10
> #4 0x0000003ce9a2fe63 in ssl23_get_client_hello () from /usr/lib64/libssl.so.10
> #5 0x0000003ce9a302f3 in ssl23_accept () from /usr/lib64/libssl.so.10
> #6 0x000000000208ebd5 in apache::thrift::transport::TSSLSocket::checkHandshake() ()
> #7 0x000000000208edbc in apache::thrift::transport::TSSLSocket::read(unsigned char*, unsigned int) ()
> #8 0x000000000208b6f3 in unsigned int apache::thrift::transport::readAll<apache::thrift::transport::TSocket>(apache::thrift::transport::TSocket&, unsigned char*, unsigned int) ()
> #9 0x0000000000cb2aa9 in apache::thrift::transport::TSaslTransport::receiveSaslMessage(apache::thrift::transport::NegotiationStatus*, unsigned int*) ()
> #10 0x0000000000cb03e4 in apache::thrift::transport::TSaslServerTransport::handleSaslStartMessage() ()
> #11 0x0000000000cb2c23 in apache::thrift::transport::TSaslTransport::doSaslNegotiation() ()
> #12 0x0000000000cb10b8 in apache::thrift::transport::TSaslServerTransport::Factory::getTransport(boost::shared_ptr<apache::thrift::transport::TTransport>) ()
> #13 0x0000000000b13e47 in apache::thrift::server::TAcceptQueueServer::SetupConnection(boost::shared_ptr<apache::thrift::transport::TTransport>) ()
> #14 0x0000000000b14932 in boost::detail::function::void_function_obj_invoker2<apache::thrift::server::TAcceptQueueServer::serve()::{lambda(int, boost::shared_ptr<apache::thrift::transport::TTransport> const&)#1}, void, int, boost::shared_ptr<apache::thrift::transport::TTransport> const&>::invoke(boost::detail::function::function_buffer&, int, boost::shared_ptr<apache::thrift::transport::TTransport> const&) ()
> #15 0x0000000000b177f9 in impala::ThreadPool<boost::shared_ptr<apache::thrift::transport::TTransport> >::WorkerThread(int) ()
> #16 0x0000000000d602af in impala::Thread::SuperviseThread(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, boost::function<void ()()>, impala::ThreadDebugInfo const*, impala::Promise<long>*) ()
> #17 0x0000000000d60aaa in boost::detail::thread_data<boost::_bi::bind_t<void, void (*)(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, boost::function<void ()()>, impala::ThreadDebugInfo const*, impala::Promise<long>*), boost::_bi::list5<boost::_bi::value<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::_bi::value<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::_bi::value<boost::function<void ()()> >, boost::_bi::value<impala::ThreadDebugInfo*>, boost::_bi::value<impala::Promise<long>*> > > >::run() ()
> #18 0x00000000012d756a in thread_proxy ()
> #19 0x0000003ce2a07aa1 in start_thread () from /lib64/libpthread.so.0
> #20 0x0000003ce26e893d in clone () from /lib64/libc.so.6
> {noformat}
> While it's not a complete fix, increasing the number of threads in {{connection_setup_pool}} makes it more robust against this kind of problem. Ideally, the number of threads in the thread pool should be configurable.
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