Implement physical plan for OFFSET

[andygrove]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.
PR #2521 adds OFFSET to the logical plan. We should implement a physical plan for it.

Describe the solution you'd like
Implement OFFSET physical plan.

Describe alternatives you've considered
None

Additional context
None

[0xPoe]

Can I take this?

[0xPoe]

I am working on this.

[0xPoe]

@andygrove Can you provide some help? I'm not quite sure how I should implement it. I see that some of the instructions in the contribution guide are out of date. I would appreciate if you could provide some guidance or reference examples.

[alamb]

Hi @hi-rustin

There is some more detail here #2521 (comment)

Here are some queries and examples that should work

Given this input:

❯ select * from (values (1), (3), (2), (10), (8)) order by column1;
+---------+
| column1 |
+---------+
| 1       |
| 2       |
| 3       |
| 8       |
| 10      |
+---------+
5 rows in set. Query took 0.010 seconds.

Trying to run with an offset results in:

❯ select * from (values (1), (3), (2), (10), (8)) order by column1 limit 1 offset 2;
Internal("Unsupported logical plan: OFFSET")
❯ select * from (values (1), (3), (2), (10), (8)) order by column1 limit 1 offset 3;
Internal("Unsupported logical plan: OFFSET")
❯ select * from (values (1), (3), (2), (10), (8)) order by column1 limit 2 offset 3;
Internal("Unsupported logical plan: OFFSET")
❯ 

The answers should be:

-- (3)
❯ select * from (values (1), (3), (2), (10), (8)) order by column1 limit 1 offset 2;
-- (8)
❯ select * from (values (1), (3), (2), (10), (8)) order by column1 limit 1 offset 3;
Internal("Unsupported logical plan: OFFSET")
-- (8) (10)
❯ select * from (values (1), (3), (2), (10), (8)) order by column1 limit 2 offset 3;
Internal("Unsupported logical plan: OFFSET")

Does that help?

[alamb]

I would try and follow the model for limit physical plan as it will be similar: https://github.com/apache/arrow-datafusion/blob/master/datafusion/core/src/physical_plan/limit.rs