Added EXPLAIN FORMAT="cost_trace"

[mjonss]

close #21897

What is changed, added or deleted? (Required)

Added cost_trace as EXPLAIN FORMAT

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[gemini-code-assist]

Summary of Changes

Hello @mjonss, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the TiDB documentation by incorporating details for the newly supported EXPLAIN FORMAT="cost_trace" option. This addition provides users with a more comprehensive understanding of query execution plans, enabling them to analyze estimated costs and the formulas used for their calculation directly within the EXPLAIN output.

Highlights

• New EXPLAIN Format Documentation: Documentation has been updated to include the cost_trace format for the EXPLAIN statement.
• Detailed Cost Analysis: The cost_trace format provides estCost for estimated cost and costFormula for the cost formula, offering deeper insights into query execution plans.

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[Copilot]

Pull Request Overview

This PR adds documentation for a new EXPLAIN FORMAT option called cost_trace in TiDB, which provides extended cost information for query execution plans.

• Added cost_trace format option to the EXPLAIN statement documentation
• The new format provides additional cost-related columns (estCost and costFormula) for query plan analysis

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[gemini-code-assist]

Code Review

This pull request adds documentation for the new cost_trace format option in the EXPLAIN statement. The change is accurate, but I've provided a suggestion to improve the wording and ensure consistency with the style guide by enclosing column names in backticks.

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-10-13 10:57:22.0106002 +0000 UTC m=+91748.087852750: ☑️ agreed by dveeden.

[dveeden]

From the check:

sql-statements/sql-statement-explain.md: 207: MD012/no-multiple-blanks Multiple consecutive blank lines [Expected: 1; Actual: 2]

[ti-chi-bot]

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