beliefer opened a new pull request, #38745:
URL: https://github.com/apache/spark/pull/38745
### What changes were proposed in this pull request?
Sometimes, the SQL exists filter which condition compares rank-like window
functions with number. For example,
```
SELECT *,
ROW_NUMBER() OVER(ORDER BY a) AS rn
FROM Tab1
WHERE rn <= 5
```
We can create a `Limit(5)` and push down it as the child of `Window`.
```
SELECT *,
ROW_NUMBER() OVER(ORDER BY a) AS rn
FROM
(SELECT *
FROM Tab1
ORDER BY a LIMIT 5) t
```
In short, it supports following pattern:
```
SELECT (... (row_number|rank|dense_rank)()
OVER (
ORDER BY ... ) AS rn)
WHERE rn (==|<|<=) k
AND other conditions
```
For these three rank functions (row_number|rank|dense_rank), the rank of a
key computed on dataset always <= its total rows of whole dataset，so we can
safely discard rows with rank > k, anywhere.
This PR also take over some functions from
https://github.com/apache/spark/pull/34367.
### Why are the changes needed?
Improve the performance.
**Micro Benchmark**
### Does this PR introduce _any_ user-facing change?
'No'.
Just update the inner implementation.
### How was this patch tested?
New tests.
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