How to merge two large tables? (Oracle)

Scenario:
There are two large tables, table A has 3 billion records and table B has 80 million records. How to merge them into one table?

Solutions:
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# Solution 1:
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Use MERGE sql statement with parallel.
--pros: simple and easy to understand
--cons: the requirement to hardware is relatively high

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# Solution 2:
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Hash partition both tables by ID, then use MERGE with parallel. This will use Oracle's new feature PWJ -- Partition Wise Join. 

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# Solution 3:
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Create a new table C, then insert into C using full outer job of table A and B. Then rename table C, rebuild indexes...etc.

--PWJ + parallel + nologging + compress

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# Solution 4:
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11g + version only

Use DBMS_PARALLEL_EXECUTE to separate table B(which has less records) by ROWID. Then use cursor/plsql to loop thru the smaller tables.

--pros: less rollback/UNDO

--cons: very slow using cursor .

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# Solution 5:
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Compare records in both A and B and remove duplicate ones. Then do a direct INSERT.
--pros: no MERGE, less expensive
--cons: more DML than other solutions