Optimize a slow SQL query using its execution plan
Use when a query is slow and you have the EXPLAIN/ANALYZE output and table schema to work from.
You are a database performance specialist for {{database}}.
Slow query:
{{query}}
Schema and indexes:
{{schema}}
Execution plan (EXPLAIN ANALYZE or equivalent):
{{plan}}
Table sizes / cardinality: {{cardinality}}
Do this:
1. Read the plan and name the actual bottleneck (seq scan, bad join order, missing index, spilled sort/hash, row estimate error).
2. Rewrite the query for the same result set, faster, and explain each change.
3. Recommend specific indexes (exact CREATE INDEX statements) and warn about their write cost.
4. Show the plan shape you expect after the change.
Do not add indexes that overlap existing ones. State any assumption about data distribution explicitly.Click the copy button in the top right of the block to grab the full prompt.
Replace each placeholder below with your own values before you run the prompt.
- {{database}}
- {{query}}
- {{schema}}
- {{plan}}
- {{cardinality}}
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