Remove weird dop logic.

[fengttt]

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 #23226

What this PR does / why we need it:

Code cleanup, remove some strange code.

---

PR Type

Enhancement

---

Description

• Remove unused getShuffleDop function and its tests

• Simplify shuffle DOP calculation to use ncpu directly

• Remove unnecessary stringzilla dependency from go.mod

---

Diagram Walkthrough

flowchart LR
  A["Complex DOP Logic"] -->|Remove| B["Simplified ncpu Usage"]
  C["getShuffleDop Function"] -->|Delete| D["Cleaner Codebase"]
  E["Unused Dependency"] -->|Remove| F["Reduced Dependencies"]

Loading

File Walkthrough

	Relevant files
Code cleanup	shuffle.go Delete unused getShuffleDop function                                          pkg/sql/plan/shuffle.go Removed getShuffleDop function (37 lines) that contained complex and unclear DOP calculation logic Function was replaced with direct ncpu usage in stats.go +0/-37
Tests	shuffle_test.go Remove getShuffleDop test cases                                                    pkg/sql/plan/shuffle_test.go Removed TestGetShuffleDop test function (63 lines) that tested the deleted getShuffleDop function Test covered various CPU and hashmap size scenarios +0/-63
Enhancement	stats.go Simplify shuffle DOP to use ncpu                                                  pkg/sql/plan/stats.go Replaced complex getShuffleDop call with direct ncpu assignment Added comment explaining the removal of "weird calculate shuffle dop logic" Simplified DOP calculation while maintaining childDop comparison logic +3/-1
Dependencies	go.mod Remove stringzilla dependency                                                        go.mod Removed unused github.com/ashvardanian/stringzilla/golang dependency +0/-1      go.sum Update checksums for removed dependency                                    go.sum Removed hash entries for github.com/ashvardanian/stringzilla/golang package +0/-2

---

[qodo-code-review]

PR Compliance Guide 🔍

Below is a summary of compliance checks for this PR:

Security Compliance
🟢	No security concerns identified No security vulnerabilities detected by AI analysis. Human verification advised for critical code.
Ticket Compliance
⚪	🎫 No ticket provided Create ticket/issue
Codebase Duplication Compliance
⚪	Codebase context is not defined Follow the guide to enable codebase context checks.
Custom Compliance
🟢	Generic: Meaningful Naming and Self-Documenting Code Objective: Ensure all identifiers clearly express their purpose and intent, making code self-documenting Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Secure Error Handling Objective: To prevent the leakage of sensitive system information through error messages while providing sufficient detail for internal debugging. Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Secure Logging Practices Objective: To ensure logs are useful for debugging and auditing without exposing sensitive information like PII, PHI, or cardholder data. Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Security-First Input Validation and Data Handling Objective: Ensure all data inputs are validated, sanitized, and handled securely to prevent vulnerabilities Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
⚪	Generic: Comprehensive Audit Trails Objective: To create a detailed and reliable record of critical system actions for security analysis and compliance. Status: Audit impact unclear: The change to use ncpu for shuffle DOP may alter runtime behavior but the diff shows no new or removed logging for critical actions, so audit trail impact cannot be determined from these hunks alone. Referred Code // there was a weird calculate shuffle dop logic here, which does not really make any sense. // just use ncpu. dop := ncpu childDop := qry.Nodes[node.Children[0]].Stats.Dop if dop < childDop { dop = childDop } Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Robust Error Handling and Edge Case Management Objective: Ensure comprehensive error handling that provides meaningful context and graceful degradation Status: Edge cases removed: Replacing getShuffleDop with direct ncpu may remove prior edge-case handling for hashmap size and child DOP interactions, but without full context it’s unclear if this degrades behavior. Referred Code // there was a weird calculate shuffle dop logic here, which does not really make any sense. // just use ncpu. dop := ncpu childDop := qry.Nodes[node.Children[0]].Stats.Dop if dop < childDop { dop = childDop } Learn more about managing compliance generic rules or creating your own custom rules
Update

Compliance status legend

🟢 - Fully Compliant
🟡 - Partial Compliant
🔴 - Not Compliant
⚪ - Requires Further Human Verification
🏷️ - Compliance label

[qodo-code-review]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
Possible issue	Prevent panic on empty children slice Add a check for len(node.Children) > 0 before accessing node.Children[0] to prevent a potential panic if a node with shuffle stats has no children. pkg/sql/plan/stats.go [1875-1882] // there was a weird calculate shuffle dop logic here, which does not really make any sense. // just use ncpu. dop := ncpu - childDop := qry.Nodes[node.Children[0]].Stats.Dop - if dop < childDop { - dop = childDop + if len(node.Children) > 0 { + childDop := qry.Nodes[node.Children[0]].Stats.Dop + if dop < childDop { + dop = childDop + } } setNodeDOP(p, rootID, dop) Apply / Chat Suggestion importance[1-10]: 6 __ Why: The suggestion correctly identifies a potential index-out-of-bounds panic and proposes a valid check, which improves the code's robustness against unexpected plan structures.	Low
Update