4 ms·
> Furthermore, simple grammar is only superficial, and the new algebra will actually bring performance improvements. For example, using ordered grouping instead
by ttfkam 3y ago
> Furthermore, simple grammar is only superficial, and the new algebra will actually bring performance improvements. For example, using ordered grouping instead of hash grouping, using merge instead of hash when associating, and so on.
Again, there appears to be disconnect with regard to SQL. SQL does not specify ordered vs hash grouping nor merge instead of hash. That is an engine implementation detail and only touched upon in DDL (schema declaration).
The query side of SQL (DML) does not specify index or grouping strategies. At all. One bit. By design.
Got a reference to a table on a different server—or even a different geographic location? Doesn't matter. The SQL query doesn't change. Local or remote, physical or virtual, reactive or static, the query language doesn't change.
- followSPL 3y agoThank you for your reply,It's a pleasure to discuss it with you.We are not only discussing the query side of SQL (DML), it is the essence of SQL, relational algebra, and the examples in the post are just for a more intuitive representation of this. The efficiency of executing a complex SQL statement can usually only be achieved through the automatic optimization function of the database engine. As you said, SQL does not specify ordered vs hash grouping nor merge instance of hash That is an engine implementation detail and only touched upon in DDL (schema declaration). Even if more optimization is done in DML, the selection of the underlying algorithm cannot be changed, at most, it makes writing SPL more convenient for users.
- followSPL 3y agoThank you for your reply,It's a pleasure to discuss it with you.We are not only discussing the query side of SQL (DML), it is the essence of SQL, relational algebra, and the examples in the post are just for a more intuitive representation of this. The efficiency of executing a complex SQL statement can usually only be achieved through the automatic optimization function of the database engine. As you said, SQL does not specify ordered vs hash grouping nor merge instance of hash That is an engine implementation detail and only touched upon in DDL (schema declaration). Even if more optimization is done in DML, the selection of the underlying algorithm cannot be changed, at most, it makes writing SQL more convenient for users.