问题
Is parallel query execution in Postgresql supported for SELECT INTO queries?
回答1:
No. Parallel execution is not available for DDL statements - only for read only queries.
The deprecated SELECT .. INTO ... creates a new table and thus it qualifies as DDL.
It is also recommended to use CREATE TABLE .. AS SELECT ... instead.
Update: Postgres 11 (to be released end of 2018) will support parallel query execution for CREATE TABLE ... AS SELECT ...
来源：https://stackoverflow.com/questions/47057891/utilizing-parallel-query-execution-in-postgresql-for-select-into