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Use sql-optimization-patterns to review [query and query plan] against [expected rows and data distribution], identify likely bottlenecks, and recommend read-only validation steps before any changes.
Required inputs
[query and query plan]
[expected rows and data distribution]
User-approved starter prompt based on a pinned source version; check current skill requirements before running. Task evidence ↗
SKILL.md
name: sql-optimization-patternsdescription: "Diagnose slow SQL with query plans, preserve query results, and verify indexing or query changes against representative data."risk: criticalsource: communitydate_added: "2026-02-27"
SQL Optimization Patterns
Diagnose slow SQL with query plans, preserve query results, and verify indexing or query changes against representative data.
Use this skill when
Debugging slow-running queries
Designing performant database schemas
Optimizing application response times
Reducing database load and costs
Improving scalability for growing datasets
Analyzing EXPLAIN query plans
Implementing efficient indexes
Resolving N+1 query problems
Do not use this skill when
The task is unrelated to sql optimization patterns
You need a different domain or tool outside this scope
Instructions
Confirm database engine/version, query parameters, expected rows, data distribution and the permitted environment. Start read-only; obtain authorization before DDL, data changes, configuration changes or maintenance.
Compare result sets before comparing performance. EXPLAIN ANALYZE executes the statement: use approved representative data, account for functions and triggers, and do not assume a transaction rollback undoes every side effect.
Record the observed plan, timing conditions and correctness checks. Indexes and query rewrites are hypotheses, not universal speed improvements.
If detailed examples are required, open resources/implementation-playbook.md.
Resources
resources/implementation-playbook.md for detailed patterns and examples.
Limitations
Use this skill only when the task clearly matches the scope described above.
Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.
Worked example
The playbook includes an executable SQLite batch-loading example with bound values and an empty-input case. The repository test exercises it alongside pagination ties and aggregation equivalence. SQLite correctness checks do not establish PostgreSQL performance or production safety.