fix the condition for runtime filters

[badboynt1]

User description

What type of PR is this?

• API-change
• BUG
• Improvement
• Documentation
• Feature
• Test and CI
• Code Refactoring

Which issue(s) this PR fixes:

issue #18387

What this PR does / why we need it:

fix the condition for runtime filters, try to push runtime filters in more cases.
fix some comment

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PR Type

Bug fix

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Description

• Fixed a bug in the calculation of selectivity for aggregation nodes in the SQL planner.
• Updated the Selectivity field to be calculated based on the ratio of outcnt to childStats.Outcnt.

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Changes walkthrough 📝

	Relevant files
Bug fix	stats.go Fix selectivity calculation for aggregation nodes                pkg/sql/plan/stats.go Fixed calculation of selectivity for aggregation nodes. Updated Selectivity to be calculated as outcnt / childStats.Outcnt. +1/-1

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PR Reviewer Guide 🔍

⏱️ Estimated effort to review: 2 🔵🔵⚪⚪⚪

🧪 No relevant tests

🔒 No security concerns identified

⚡ Key issues to review Potential Division by Zero The new calculation for Selectivity (outcnt / childStats.Outcnt) could potentially lead to a division by zero if childStats.Outcnt is zero.

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PR Code Suggestions ✨

Category	Suggestion	Score
Possible issue	✅ Add a check to prevent division by zero when calculating selectivity Suggestion Impact: The commit addressed the division by zero issue by setting the selectivity to a default value of 1, which avoids the division operation entirely. code diff: - node.Stats.Selectivity = outcnt / childStats.Outcnt + node.Stats.Selectivity = 1 Consider adding a check to prevent division by zero when childStats.Outcnt is 0. This will improve the robustness of the code and prevent potential runtime errors. pkg/sql/plan/stats.go [816] -node.Stats.Selectivity = outcnt / childStats.Outcnt +if childStats.Outcnt > 0 { + node.Stats.Selectivity = outcnt / childStats.Outcnt +} else { + node.Stats.Selectivity = 0 // or another appropriate default value +} Apply this suggestion Suggestion importance[1-10]: 9 Why: This suggestion addresses a potential runtime error by adding a check to prevent division by zero, which is crucial for the robustness of the code.	9
Best practice	Clamp the calculated selectivity value between 0 and 1 Consider clamping the selectivity value between 0 and 1 to ensure it remains within a valid range for statistical calculations. pkg/sql/plan/stats.go [816] -node.Stats.Selectivity = outcnt / childStats.Outcnt +node.Stats.Selectivity = math.Max(0, math.Min(1, outcnt / childStats.Outcnt)) Apply this suggestion Suggestion importance[1-10]: 7 Why: Clamping the selectivity value ensures it remains within a valid range, improving the reliability of statistical calculations, though it is not as critical as preventing division by zero.	7