Andrey Zagrebin created FLINK-16686:
---------------------------------------
Summary: [State TTL] Make user class loader available in native
RocksDB compaction thread
Key: FLINK-16686
URL: https://issues.apache.org/jira/browse/FLINK-16686
Project: Flink
Issue Type: Bug
Components: Runtime / State Backends
Affects Versions: 1.8.0
Reporter: Andrey Zagrebin
The issue is initially reported
[here|https://stackoverflow.com/questions/60745711/flink-kryo-serializer-because-chill-serializer-couldnt-be-found].
The problem is that the java code of Flink compaction filter is called from
RocksDB native C++ code. It is called in the context of the native compaction
thread. RocksDB has utilities to create java Thread context for the Flink java
callback. Presumably, the Java thread context class loader is not set at all
and if it is queried then it produces NullPointerException.
The provided report enabled a list state with TTL. The compaction filter has to
deserialise elements to check expiration. The deserialiser relies on Kryo which
queries the thread context class loader which is expected to be the user class
loader of the task but turns out to be null.
We should investigate how to pass the user class loader to the compaction
thread of the list state with TTL.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
