Execution Plan Analysis

Use this skill to triage SQL Server actual or estimated execution plans, especially .sqlplan ShowPlan XML. Treat the plan as evidence, not a verdict: validate schema, data types, indexes, row counts, partitioning, parameter values, and local-vs-linked-server execution before recommending rewrites or indexes.

Required Inputs

Ask for the smallest set needed to verify the plan:

• SQL Server version, database compatibility level, and Azure SQL vs boxed SQL Server.
• Actual plan when available; estimated plan if execution is unsafe.
• Query text, parameter values, SET options if relevant, and runtime symptoms.
• Table DDL, column data types, indexes, statistics age, partition scheme/function, and row counts.
• Whether referenced objects are local, remote linked servers, views, table-valued functions, or temp tables.
• Allowed changes: query rewrite, statistics update, index add/drop/change, computed column, staging table, or no code change.

Use ../_shared/optimization-intake.md and ../_shared/assumption-tracker.md for intake and assumption status tracking.

Workflow