How Do I Merge Small Files?
If a large number of small files are generated during SQL execution, job execution and table query will take a long time. In this case, you should merge small files.
You are advised to use temporary tables for data transfer. There is a risk of data loss in self-read and self-write operations during unexpected exceptional scenarios.
Run the following SQL statements:
INSERT OVERWRITE TABLE tablenameselect * FROM tablenameDISTRIBUTE BY floor(rand()*20)
Parent topic: SQL Job Development