Good morning, Team - any update on this? - Mansi
On Thu, Dec 28, 2017 at 12:32 AM, Manaswini Maharana <mmahar...@cloudera.com > wrote: > Hello team, I'd like to contribute to Impala and would like to start it > with this (IMPALA-6296) jira. Can I please have it assigned to me? > > My development environment is ready. I'm on ubuntu 16.04 so yes some > challenges to set up the environment especially with the LD_LIBRARY_PATH > issues. So far I'm able to work past it and might ask for another pair of > eyes to ensure it follows standard. The builds are going fine and runs a > bit longer as I've disabled the -so. Apart from setup, I'm was able to > reproduce the issue and might have been ready with the fix which I'd like > to discuss once I'm officially assigned the jira. > > Thanks Tim, for the instructions, it was very helpful. > > > Thanks! > Mansi > > > > On Tue, Dec 12, 2017 at 8:24 PM, Tim Armstrong <tarmstr...@cloudera.com> > wrote: > >> If you'd like to contribute a patch to Impala, but aren't sure what >> you want to work on, you can look at Impala's newbie issues: >> https://issues.apache.org/jira/issues/?filter=12341668. You can find >> detailed instructions on submitting patches at >> https://cwiki.apache.org/confluence/display/IMPALA/Contributing+to+Impala >> . >> This is a walkthrough of a ticket a new contributor could take on, >> with hopefully enough detail to get you going but not so much to take >> away the fun. >> >> How can we solve https://issues.apache.org/jira/browse/IMPALA-6296, >> "DCheck in CodegenSymbolEmitter when --asm_module_dir is set on debug >> build >> "? >> First, make sure you have your development environment set up. Let's >> see if we can reproduce the issue. >> >> Create a directory for the codegen modules then start impala-server >> $ mkdir codegen-modules >> $ start-impala-cluster.py --impalad_args="--opt_module_d >> ir=codegen-modules >> --unopt_module_dir=codegen-modules --asm_module_dir=codegen-modules" >> >> Now run a query through Impala. I chose this query because it uses >> Impala's >> runtime code generation ("codegen") to improve performance >> $ bin/impala-shell.sh -q "select count(*) from tpch.lineitem" >> >> After a few seconds, you should see an error from Impala crashing: >> Error communicating with impalad: TSocket read 0 bytes >> Could not execute command: select count(*) from tpch.lineitem >> >> Attempting to run any further queries will fail because of the crashed >> Impala daemons: >> $ impala-shell.sh -q "select count(*) from tpch.lineitem"; >> Starting Impala Shell without Kerberos authentication >> Error connecting: TTransportException, Could not connect to >> localhost:21000 >> Not connected to Impala, could not execute queries. >> >> If you look at logs/cluster/impalad.ERROR you will see a message >> explaining >> the crash - we hit a DCHECK (a.k.a. an assertion): >> >> F1212 17:10:07.642722 9138 codegen-symbol-emitter.cc:90] Check failed: >> perf_map_.find(obj.getData().data()) != perf_map_.end() >> *** Check failure stack trace: *** >> @ 0x3be16ed google::LogMessage::Fail() >> @ 0x3be2f92 google::LogMessage::SendToLog() >> @ 0x3be10c7 google::LogMessage::Flush() >> @ 0x3be468e google::LogMessageFatal::~LogMessageFatal() >> @ 0x1b354f1 >> impala::CodegenSymbolEmitter::NotifyFreeingObject() >> @ 0x375b791 llvm::MCJIT::NotifyFreeingObject() >> @ 0x375b811 llvm::MCJIT::~MCJIT() >> @ 0x375bfc9 llvm::MCJIT::~MCJIT() >> @ 0x1b265ba std::default_delete<>::operator()() >> @ 0x1b23e21 std::unique_ptr<>::reset() >> @ 0x1b11198 impala::LlvmCodeGen::Close() >> @ 0x182194d impala::RuntimeState::ReleaseResources() >> @ 0x1893a35 impala::FragmentInstanceState::Close() >> @ 0x1890d58 impala::FragmentInstanceState::Exec() >> @ 0x1879afa impala::QueryState::ExecFInstance() >> @ 0x18783bc >> _ZZN6impala10QueryState15StartFInstancesEvENKUlvE_clEv >> @ 0x187a739 >> _ZN5boost6detail8function26void_function_obj_invoker0IZN6imp >> ala10QueryState15StartFInstancesEvEUlvE_vE6invokeERNS1_15function_bufferE >> @ 0x17c7200 boost::function0<>::operator()() >> @ 0x1abdf8b impala::Thread::SuperviseThread() >> @ 0x1ac6b16 boost::_bi::list4<>::operator()<>() >> @ 0x1ac6a59 boost::_bi::bind_t<>::operator()() >> @ 0x1ac6a1c boost::detail::thread_data<>::run() >> @ 0x2d6b08a thread_proxy >> @ 0x7fcb5ff146ba start_thread >> @ 0x7fcb5fc4a3dd clone >> >> It looks like something is wrong with the code - 'perf_map_' doesn't have >> anything in it. If we look a few lines above, it looks like 'perf_map_' is >> only filled in if 'emit_perf_map_' is true. >> >> if (emit_perf_map_) { >> lock_guard<SpinLock> perf_map_lock(perf_map_lock_); >> DCHECK(perf_map_.find(obj.getData().data()) == perf_map_.end()); >> perf_map_[obj.getData().data()] = std::move(perf_map_entries); >> WritePerfMapLocked(); >> } >> >> Maybe we should also be checking 'emit_perf_map_' before the DCHECK? >> >> After you have fixed this bug, you should be able to run the query without >> Impala crashing and you should be able to inspect the assembly generated >> by >> Impala in codegen-modules/*.asm >> >> Have fun, and don't be afraid to ask dev@impala.apache.org is you have >> any questions! >> > >
