support order by limit optimization for non-sorted columns

[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 #17367

What this PR does / why we need it:

support order by limit optimization for non-sorted columns

---

PR Type

enhancement

---

Description

• Removed a condition in the handleMessgaeFromTopToScan function that checked the sort order of a column, optimizing the order by limit for non-sorted columns.
• Simplified the logic for processing messages in the query plan, potentially improving performance.

---

Changes walkthrough 📝

	Relevant files
Enhancement	message.go Optimize order by limit for non-sorted columns                      pkg/sql/plan/message.go Removed a condition that checks the sort order of a column in the scan node. Simplified the logic for handling messages from top to scan nodes. +0/-3

---

💡 PR-Agent usage:
Comment /help on the PR to get a list of all available PR-Agent tools and their descriptions

[codiumai-pr-agent-pro]

PR-Agent was enabled for this repository. To continue using it, please link your git user with your CodiumAI identity here.

PR Reviewer Guide 🔍

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

🧪 No relevant tests

🔒 No security concerns identified

⚡ Key issues to review Potential Performance Impact Removal of the sort order check might lead to unexpected behavior or performance issues for certain queries involving non-sorted columns.

[codiumai-pr-agent-pro]

PR-Agent was enabled for this repository. To continue using it, please link your git user with your CodiumAI identity here.

PR Code Suggestions ✨

Category	Suggestion	Score
Maintainability	Add a comment explaining the removal of the sort order check Consider adding a comment explaining why the check for the sort order of the column was removed. This will help future maintainers understand the reasoning behind this change. pkg/sql/plan/message.go [72-73] if orderByCol.Col.RelPos != scanNode.BindingTags[0] { return } +// The check for column sort order was removed to support order by limit optimization for non-sorted columns Apply this suggestion Suggestion importance[1-10]: 8 Why: Adding a comment to explain the removal of the sort order check improves maintainability by providing context for future developers, helping them understand the rationale behind the change.	8
Possible issue	Add a check to ensure the column is sorted before applying the optimization Consider adding a check to ensure that the column is actually sorted before applying the optimization. This will prevent potential issues with unsorted columns. pkg/sql/plan/message.go [64-73] orderByCol, ok := node.OrderBy[0].Expr.Expr.(*plan.Expr_Col) if !ok { return } scanNode := builder.qry.Nodes[scanID] if len(scanNode.OrderBy) != 0 { panic("orderby in scannode should be nil!") } if orderByCol.Col.RelPos != scanNode.BindingTags[0] { return } +if !isColumnSorted(scanNode.TableDef, orderByCol.Col.ColPos) { + return +} Apply this suggestion Suggestion importance[1-10]: 7 Why: The suggestion adds a check to ensure that the column is sorted, which could prevent potential issues with unsorted columns. However, it may not align with the intended simplification of the logic in the PR.	7