databend feat(planner): support tuple map access pushdown to storage

feat(planner): support tuple map access pushdown to storage

Open b41sh opened this issue 2 years ago • 1 comments

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Summary

Use map access syntax to select tuple inner columns and push down the query to the storage layer, only need to read the required columns.

ColumnEntry add field path_indices as an index to find inner columns.
add tuple inner columns to Metadata.
modify the Extras field projection as enum Projection in order to access inner columns.

for example

CREATE TABLE t(id Int, t Tuple(a Tuple(m Int64, n Int64), b Tuple(x Int64, y Int64))) Engine = Fuse;
INSERT INTO t (id, t) VALUES(1, ((10, 11), (20, 21))), (2, ((30, 31), (40, 41)));
SELECT t:a:m, t:a:n, t:b[0], t:b[1] FROM t;

+-------+-------+--------+--------+
| t:a:m | t:a:n | t:b[0] | t:b[1] |
+-------+-------+--------+--------+
| 10    | 11    | 20     | 21     |
| 30    | 31    | 40     | 41     |
+-------+-------+--------+--------+

Fixes #6794