通过调优提高 Oracle 中的查询性能

Question

I'm doing an ETL with a table with 100 million records where I capture the information from TERADATA and import it into ORACLE. The process is taking too long and I want to know if there is any way to improve the performance of my query with some tuning.

 MERGE INTO TABLE_A TB USING ( select t.COLUMN_A as COLUMN_A_OLD from TABLE_B t left outer join STAGE s on s.COLUMN_B = t.COLUMN_B and s.COLUMN_C = t.COLUMN_C and s.COLUMN_D = t.COLUMN_D and s.COLUMN_E = t.COLUMN_E and s.COLUMN_F = to_date('yyyy-mm-dd 00:00:00','yyyy-mm-dd hh24:mi:ss') where t.COLUMN_F = to_date('2100-12-31 00:00:00','yyyy-mm-dd hh24:mi:ss') and s.COLUMN_C is null ) stg on ( stg.COLUMN_A_OLD = tb.COLUMN_A ) WHEN MATCHED THEN UPDATE SET TB.COLUMN_F = sysdate, TB.COLUMN_G = $$PARAMETER , TB.COLUMN_H = sysdate; commit;

Thanks.

Answer 1

Have you tried something like this?

alter session enable parallel dml;

 merge /*+ parallel(10) */ into ….

The PARALLEL hint will enable read-parallelism, but to also enable write-parallelism you will need to either run the above ALTER SESSION command or use the hint /*+ ENABLE_PARALLEL_DML */.