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From Vincent Tran <vtt...@cloudera.com>
Subject Re: New Impala Contributors: IMPALA-6296
Date Fri, 29 Dec 2017 15:02:44 GMT
You should be able to just simply "assign to me" if you are signed into ADD
Jira.

On Dec 29, 2017 9:54 AM, "Manaswini Maharana" <mmaharana@cloudera.com>
wrote:

> Good morning, Team - any update on this?
>
> - Mansi
>
>
> On Thu, Dec 28, 2017 at 12:32 AM, Manaswini Maharana <
> mmaharana@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 <tarmstrong@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!
> >>
> >
> >
>

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