[英]Improve query performance in Oracle with 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;
谢谢。
你有没有尝试过这样的事情?
alter session enable parallel dml;
merge /*+ parallel(10) */ into ….
PARALLEL 提示将启用读并行,但要同时启用写并行,您需要运行上述 ALTER SESSION 命令或使用提示 /*+ ENABLE_PARALLEL_DML */。
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