Pranay Singh created IMPALA-7168:
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Summary: DML query may hang if CatalogUpdateCallback() encounters
repeated error
Key: IMPALA-7168
URL: https://issues.apache.org/jira/browse/IMPALA-7168
Project: IMPALA
Issue Type: Bug
Components: Catalog
Affects Versions: Impala 2.12.0, Impala 3.0, Impala 2.11.0, Impala 2.10.0,
Impala 2.9.0
Reporter: Pranay Singh
DML queries or INSERT will encounter a hang, if
exec_env_->frontend()->UpdateCatalogCache() in
ImpalaServer::CatalogUpdateCallback encounters repeated error like ENOMEM.
This happens with SYNC_DDL set to 1 when the coordinator node is waiting for
it's catalog version to become current.
The scenario shows up like this, lets say there are two coordinator nodes ,
Node A, Node B
and catalogd and statestored are running on Node C.
a) CREATE TABLE is executed on Node A, with SYNC_DDL set to 1, the thread
running the query is going to block in
impala::ImpalaServer::ProcessCatalogUpdateResult(), waiting for it's catalog
version to become current.
b) Meanwhile statestored running on Node C would call
ImpalaServer::CatalogUpdateCallback on Node B via thrift RPC to do a delta
topic update, which would not happen if we encounter repeated errors, say front
end is low on memory (low JVM heap situation).
c) In such case Node A will wait indefinitely, till Node B is shutdown
voluntarily.Note this is case where Node B is reachable (hearbeat is fine, but
bad node)
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