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Posted to issues@flink.apache.org by "Rui Li (Jira)" <ji...@apache.org> on 2020/12/09 13:35:00 UTC
[jira] [Updated] (FLINK-20549) New ExecutionContext doesn't inherit
classloader from previous context
[ https://issues.apache.org/jira/browse/FLINK-20549?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Rui Li updated FLINK-20549:
---------------------------
Description:
When users change session properties from SQL client, {{LocalExecutor}} creates a new {{ExecutionContext}}. The new {{ExecutionContext}} inherits {{SessionState}} from previous session, which means the loaded Catalog/Module instances are reused. Since Catalog/Module are pluggable, the classes may come from user jars. However the new {{ExecutionContext}} doesn't inherit classloader from previous session. That means when the Catalog/Module instances are used, the thread context classloader and the defining classloader are different.
This can cause problems such as:
# Define a {{HiveModule}} in yaml file. Don't put the hive connector jar under lib folder, but add it through the {{"-l"}} option when launching the SQL client.
# Run some query using a hive built-in function.
# Change some session property to trigger a re-creation of {{ExecutionContext}}.
# Run the same query again and it would fail because the hive built-in function cannot be instantiated.
> New ExecutionContext doesn't inherit classloader from previous context
> ----------------------------------------------------------------------
>
> Key: FLINK-20549
> URL: https://issues.apache.org/jira/browse/FLINK-20549
> Project: Flink
> Issue Type: Bug
> Components: Table SQL / Client
> Reporter: Rui Li
> Priority: Major
>
> When users change session properties from SQL client, {{LocalExecutor}} creates a new {{ExecutionContext}}. The new {{ExecutionContext}} inherits {{SessionState}} from previous session, which means the loaded Catalog/Module instances are reused. Since Catalog/Module are pluggable, the classes may come from user jars. However the new {{ExecutionContext}} doesn't inherit classloader from previous session. That means when the Catalog/Module instances are used, the thread context classloader and the defining classloader are different.
> This can cause problems such as:
> # Define a {{HiveModule}} in yaml file. Don't put the hive connector jar under lib folder, but add it through the {{"-l"}} option when launching the SQL client.
> # Run some query using a hive built-in function.
> # Change some session property to trigger a re-creation of {{ExecutionContext}}.
> # Run the same query again and it would fail because the hive built-in function cannot be instantiated.
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