Wenzhe Zhou created IMPALA-12909:
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Summary: Generate distributed plan for query accessing multiple
JDBC tables
Key: IMPALA-12909
URL: https://issues.apache.org/jira/browse/IMPALA-12909
Project: IMPALA
Issue Type: Sub-task
Components: Frontend
Reporter: Wenzhe Zhou
For a query which access multiple JDBC tables, Planner generate single node
plan. It's better to generate distributed plan so that Impala could open
multiple JDBC connections in parallel. This restriction is due to current
design of External data source framework because scan is single threaded.
DataSourceScanNode cannot run in node other than coordinator.
There is no issue for query with join between JDBC table and non JDBC table. We
have this issue only for all scans as JDBC table scans.
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