log some filter exprs

[XuPeng-SH]

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 #14518

What this PR does / why we need it:

log some slow ranges expr
log some exprs

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PR Type

Enhancement

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Description

• Introduced traceFilterExprInterval to manage logging intervals for filter expressions.
• Added logic in Ranges method to conditionally log filter expressions based on the length of ranges.
• Implemented logging for filter expressions in NewReader method when enableLogFilterExpr is set.
• Added enableLogFilterExpr atomic boolean to txnTable struct to control logging behavior.

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Changes walkthrough 📝

Relevant files

Enhancement

txn_table.go Add conditional logging for filter expressions based on range length pkg/vm/engine/disttae/txn_table.go Introduced traceFilterExprInterval to manage logging intervals. Added logic to conditionally log filter expressions based on range length. Implemented logging for filter expressions in Ranges and NewReader methods. +47/-0    types.go Add atomic boolean for enabling filter expression logging pkg/vm/engine/disttae/types.go Added enableLogFilterExpr atomic boolean to txnTable struct. +1/-0

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PR Reviewer Guide 🔍

⏱️ Estimated effort to review: 3 🔵🔵🔵⚪⚪

🧪 No relevant tests

🔒 No security concerns identified

⚡ Key issues to review Logging Interval Logic: The logic to determine when to log based on traceFilterExprInterval and rangesLen seems complex and could be error-prone. Consider simplifying this logic or adding more comments to explain the thresholds and the step values. Performance Impact: Frequent logging based on the range length could potentially impact performance, especially for large datasets. It would be beneficial to evaluate the performance implications of this logging, particularly under high load.

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PR Code Suggestions ✨

Category	Suggestion	Score
Possible issue	Ensure atomicity of traceFilterExprInterval updates to avoid race conditions The traceFilterExprInterval.Add(step) and traceFilterExprInterval.Store(0) operations should be atomic to avoid race conditions. Use CompareAndSwap to ensure atomicity. pkg/vm/engine/disttae/txn_table.go [601-604] -if traceFilterExprInterval.Add(step) >= 500000 { - traceFilterExprInterval.Store(0) - tbl.enableLogFilterExpr.Store(true) +for { + current := traceFilterExprInterval.Load() + if traceFilterExprInterval.CompareAndSwap(current, current+step) && current+step >= 500000 { + traceFilterExprInterval.Store(0) + tbl.enableLogFilterExpr.Store(true) + break + } } Apply this suggestion Suggestion importance[1-10]: 8 Why: The suggestion correctly identifies a potential race condition in the handling of traceFilterExprInterval and proposes a safer atomic operation which is crucial for thread safety.	8
	Ensure exprs is not nil before formatting to avoid nil pointer dereference Add a check to ensure exprs is not nil before calling plan2.FormatExprs(exprs) to avoid potential nil pointer dereference. pkg/vm/engine/disttae/txn_table.go [611-618] +exprsStr := "nil" +if exprs != nil { + exprsStr = plan2.FormatExprs(exprs) +} logutil.Info( "TXN-FILTER-RANGE-LOG", zap.String("name", tbl.tableDef.Name), - zap.String("exprs", plan2.FormatExprs(exprs)), + zap.String("exprs", exprsStr), zap.Int("ranges-len", ranges.Len()), zap.Uint64("tbl-id", tbl.tableId), zap.String("txn", tbl.db.op.Txn().DebugString()), ) Apply this suggestion Suggestion importance[1-10]: 7 Why: This suggestion correctly addresses a potential nil pointer dereference which is a critical issue. However, the existing code does not directly show usage of exprs in a context that would lead to a nil dereference, but the precaution is valuable.	7
Enhancement	Use a single call to ranges.Len() and a switch statement for better readability Avoid calling ranges.Len() multiple times by storing its result in a variable. pkg/vm/engine/disttae/txn_table.go [591-600] rangesLen := ranges.Len() -if rangesLen < 5 { +switch { +case rangesLen < 5: step = uint64(1) -} else if rangesLen < 10 { +case rangesLen < 10: step = uint64(5) -} else if rangesLen < 20 { +case rangesLen < 20: step = uint64(10) -} else { +default: step = uint64(0) } Apply this suggestion Suggestion importance[1-10]: 6 Why: The suggestion improves code readability by using a switch statement, which is a good practice for handling multiple conditions. However, the existing code already stores ranges.Len() in a variable, so the main improvement is the switch usage.	6
	Simplify the conditions that set tbl.enableLogFilterExpr to true Combine the two conditions that set tbl.enableLogFilterExpr to true into a single condition to simplify the code. pkg/vm/engine/disttae/txn_table.go [606-608] -if rangesLen >= 20 { +if rangesLen >= 20 || traceFilterExprInterval.Add(step) >= 500000 { + traceFilterExprInterval.Store(0) tbl.enableLogFilterExpr.Store(true) } Apply this suggestion Suggestion importance[1-10]: 5 Why: The suggestion to simplify the conditions is valid and improves code readability, but it's a moderate improvement and not critical for functionality or performance.	5