Tim Armstrong created IMPALA-9788:
-------------------------------------
Summary: Weird things happen when impalad restarts with different
hostname but same IP
Key: IMPALA-9788
URL: https://issues.apache.org/jira/browse/IMPALA-9788
Project: IMPALA
Issue Type: Bug
Components: Backend
Affects Versions: Impala 3.4.0
Reporter: Tim Armstrong
Assignee: Sahil Takiar
Attachments: get-root-sink-resolved.txt
I was messing around with running impala in a single-node dockerized
configuration and ran into a bunch of weirdness stemming when I restarted the
impalad. It got into a state where where was a new and old statestore
registration with the same IP/port and different hostnames (since docker
generates new hostnames for each incarnation of the container).
I saw a crash in Coordinator::GetRootSink(). The cause of that is the
coordinator treating the same impalad as two distinct backends, and sending two
execute RPCs to the backend (this is a single node cluster).
{noformat}
I0528 17:32:41.760128 573 coordinator.cc:143]
f84b158b036445ad:3a9defdf00000000] Exec()
query_id=f84b158b036445ad:3a9defdf00000000 stmt=SELECT COUNT(*) FROM
tpcds_kudu.call_center
I0528 17:32:41.760670 573 coordinator.cc:463]
f84b158b036445ad:3a9defdf00000000] starting execution on 2 backends for
query_id=f84b158b036445ad:3a9defdf00000000
..
I0528 17:32:41.762449 78 control-service.cc:153]
f84b158b036445ad:3a9defdf00000000] ExecQueryFInstances():
query_id=f84b158b036445ad:3a9defdf00000000 coord=a16ac03fc53b:22000 #instances=1
I0528 17:32:41.761706 79 control-service.cc:153]
f84b158b036445ad:3a9defdf00000000] ExecQueryFInstances():
query_id=f84b158b036445ad:3a9defdf00000000 coord=a16ac03fc53b:22000 #instances=4
..
Wrote minidump to
/opt/impala/logs/minidumps/impalad/15727084-c931-49e1-62d37e86-75cfe0f6.dmp
#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x00000000011a0d50, pid=1, tid=0x00007f92b5e8c700
#
# JRE version: OpenJDK Runtime Environment (8.0_242-b08) (build
1.8.0_242-8u242-b08-0ubuntu3~18.04-b08)
# Java VM: OpenJDK 64-Bit Server VM (25.242-b08 mixed mode linux-amd64
compressed oops)
# Problematic frame:
Wrote minidump to
/opt/impala/logs/minidumps/impalad/15727084-c931-49e1-62d37e86-75cfe0f6.dmp
# C [impalad+0xda0d50] impala::FragmentInstanceState::GetRootSink() const+0x0
#
# Core dump written. Default location: /opt/impala/core or core.1
#
# An error report file with more information is saved as:
# /opt/impala/hs_err_pid1.log
#
# If you would like to submit a bug report, please visit:
# http://bugreport.java.com/bugreport/crash.jsp
#
[error occurred during error reporting , id 0xb]
{noformat}
CC [~twm378]
At a separate time I saw it trip the "Tried to add existing backend to executor
group" case in ExecutorGroup::AddExecutor().
{Noformat}
>>void ExecutorGroup::AddExecutor(const BackendDescriptorPB& be_desc) {
// be_desc.is_executor can be false for the local backend when scheduling
queries to run
// on the coordinator host.
DCHECK(!be_desc.ip_address().empty());
Executors& be_descs = executor_map_[be_desc.ip_address()];
auto eq = [&be_desc](const BackendDescriptorPB& existing) {
// The IP addresses must already match, so it is sufficient to check the
port.
DCHECK_EQ(existing.ip_address(), be_desc.ip_address());
return existing.address().port() == be_desc.address().port();
};
if (find_if(be_descs.begin(), be_descs.end(), eq) != be_descs.end()) {
LOG(DFATAL) << "Tried to add existing backend to executor group: "
<< be_desc.krpc_address();
return;
}
if (!CheckConsistencyOrWarn(be_desc)) {
LOG(WARNING) << "Ignoring inconsistent backend for executor group: "
<< be_desc.krpc_address();
return;
}
if (be_descs.empty()) {
executor_ip_hash_ring_.AddNode(be_desc.ip_address());
}
be_descs.push_back(be_desc);
executor_ip_map_[be_desc.address().hostname()] = be_desc.ip_address();
}
{noformat}
I'm not sure if using the hostname to identify impalads is even useful at this
point, we could probably simplify this by using IP address only.
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