New Join Reorder #6225
Description
background
The current JoinReorder algorithm mainly sorts according to the star model, and only considers the query association relationship between the table and the table.
His problem is:
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Only applicable to user data whose data model is a star model, data of other models cannot be sorted.
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Regardless of the cost consumption of the table, it is impossible to determine the size of the join table relationship, and the real query optimization ability is weak.
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It is not possible to avoid possible time-consuming joins such as cross joins by sorting.