advantage

shortcoming

proposal 1: writing order first

(we support)

• easy to resolve the hint conflict

• the first hint by the written order may be not the most optimal strategy

proposal 2: high priority first

(different join hints have different priority)

• always choose the better join strategy by the priority we define.
• user can write two or more two join hints and all of them can be considered by actual scene

• hard to define the priority when a new join strategy will be added
• user can't control the order of trying different join strategies

proposal 3: least cost first

• always choose the faster join strategy by CBO
• user can write two or more join hints and all of them can be considered by CBO

• It depends on CBO and may lead to an uncontrollable behavior.
• user can't control the order of trying different join strategies

proposal 4: only try the first hint

• easy to resolve the hint conflict

• sometimes user want to try both two join hints but this proposal may only try one join hint

proposal 5: ignore conflict hints

• easy enough to resolve the hint conflict

• sometimes user want to try both two join hints but this proposal will ignore all of them