Treat Low Confidence, 0 estimations as unknown during joins

[abhinavmuk04]

Description

Treat Low Confidence, 0 estimations as unknown during joins

Motivation and Context

When a node has a low confidence and a 0 estimation it is likely due to the fact that there has been multiple filters pushed down on it. Additionally, sometimes this estimation can actually be so incorrect that it can have us broadcasting the wrong side entirely leading to a failed query. This will help us avoid this.

Impact

This can result in faster query execution times and improved overall performance.

Test Plan

Create plans tests where there are example of low confidence 0 estimation statistics and ensure behavior is as expected from the change. For more specific details on test plan please visit here

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• Please make sure your submission complies with our development, formatting, commit message, and attribution guidelines.
• PR description addresses the issue accurately and concisely. If the change is non-trivial, a GitHub Issue is referenced.
• Documented new properties (with its default value), SQL syntax, functions, or other functionality.
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• Adequate tests were added if applicable.
• CI passed.

Release Notes

* Add treatment of low confidence, zero estimations as ``UNKNOWN`` during joins,
   with the ``treat-low-confidence-zero-estimation-as-unknown`` session property :pr:`23047`

[feilong-liu]

Also we need to have a session property to guard this feature.

[steveburnett]

I think a word ("joins") is missing from the release note entry. Suggested edit:

* Add treatment of low confidence, zero estimations as ``UNKNOWN`` during joins, with the ``treat-low-confidence-zero-estimation-as-unknown`` session property :pr:`23047`