From e0d87f7415eb08b7d7308b1b154b62c9953a51ec Mon Sep 17 00:00:00 2001 From: shubham070 Date: Sun, 20 Jul 2025 13:37:05 +0530 Subject: [PATCH] Add comprehensive SQL and PostgreSQL prompt collection - Add sql-code-review.prompt.md: Universal SQL code review for security, maintainability, and quality standards - Add sql-optimization.prompt.md: Universal SQL performance optimization for query tuning and indexing - Add postgresql-code-review.prompt.md: PostgreSQL-specific code review focusing on PG best practices and anti-patterns - Add postgresql-optimization.prompt.md: PostgreSQL-specific development assistant for unique PG features (JSONB, arrays, custom types) This creates a complete 4-prompt ecosystem with zero overlap: - Universal SQL (code quality + performance) for cross-database compatibility - PostgreSQL-specific (code quality + performance) for PG-exclusive features Each prompt serves distinct, isolated purposes while complementing each other for comprehensive SQL development support. --- README.md | 4 + prompts/postgresql-code-review.prompt.md | 213 ++++++++++++ prompts/postgresql-optimization.prompt.md | 405 ++++++++++++++++++++++ prompts/sql-code-review.prompt.md | 302 ++++++++++++++++ prompts/sql-optimization.prompt.md | 297 ++++++++++++++++ 5 files changed, 1221 insertions(+) create mode 100644 prompts/postgresql-code-review.prompt.md create mode 100644 prompts/postgresql-optimization.prompt.md create mode 100644 prompts/sql-code-review.prompt.md create mode 100644 prompts/sql-optimization.prompt.md diff --git a/README.md b/README.md index 30e118a..3d09e17 100644 --- a/README.md +++ b/README.md @@ -110,7 +110,11 @@ Ready-to-use prompt templates for specific development scenarios and tasks, defi | [My Issues](prompts/my-issues.prompt.md) | List my issues in the current repository | [![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://vscode.dev/redirect?url=vscode%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fmy-issues.prompt.md) [![Install in VS Code](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://insiders.vscode.dev/redirect?url=vscode-insiders%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fmy-issues.prompt.md) | | [My Pull Requests](prompts/my-pull-requests.prompt.md) | List my pull requests in the current repository | [![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://vscode.dev/redirect?url=vscode%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fmy-pull-requests.prompt.md) [![Install in VS Code](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://insiders.vscode.dev/redirect?url=vscode-insiders%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fmy-pull-requests.prompt.md) | | [Next Intl Add Language](prompts/next-intl-add-language.prompt.md) | Add new language to a Next.js + next-intl application | [![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://vscode.dev/redirect?url=vscode%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fnext-intl-add-language.prompt.md) [![Install in VS Code](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://insiders.vscode.dev/redirect?url=vscode-insiders%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fnext-intl-add-language.prompt.md) | +| [PostgreSQL Code Review Assistant](prompts/postgresql-code-review.prompt.md) | PostgreSQL-specific code review focusing on PostgreSQL best practices, anti-patterns, and PostgreSQL-unique quality standards. | [![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://vscode.dev/redirect?url=vscode%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fpostgresql-code-review.prompt.md) [![Install in VS Code](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://insiders.vscode.dev/redirect?url=vscode-insiders%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fpostgresql-code-review.prompt.md) | +| [PostgreSQL Development Assistant](prompts/postgresql-optimization.prompt.md) | PostgreSQL-specific development assistant focusing on unique PostgreSQL features, advanced data types, and PostgreSQL-exclusive capabilities. Complements general SQL optimization and code review. | [![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://vscode.dev/redirect?url=vscode%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fpostgresql-optimization.prompt.md) [![Install in VS Code](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://insiders.vscode.dev/redirect?url=vscode-insiders%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fpostgresql-optimization.prompt.md) | | [Review And Refactor](prompts/review-and-refactor.prompt.md) | Review and refactor code in your project according to defined instructions | [![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://vscode.dev/redirect?url=vscode%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Freview-and-refactor.prompt.md) [![Install in VS Code](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://insiders.vscode.dev/redirect?url=vscode-insiders%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Freview-and-refactor.prompt.md) | +| [SQL Code Review](prompts/sql-code-review.prompt.md) | Universal SQL code review focusing on security, maintainability, and code quality standards across all SQL databases. Complements SQL optimization prompt. | [![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://vscode.dev/redirect?url=vscode%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fsql-code-review.prompt.md) [![Install in VS Code](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://insiders.vscode.dev/redirect?url=vscode-insiders%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fsql-code-review.prompt.md) | +| [SQL Performance Optimization Assistant](prompts/sql-optimization.prompt.md) | Universal SQL performance optimization assistant for query tuning, indexing strategies, and database performance across all SQL databases. | [![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://vscode.dev/redirect?url=vscode%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fsql-optimization.prompt.md) [![Install in VS Code](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://insiders.vscode.dev/redirect?url=vscode-insiders%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fsql-optimization.prompt.md) | | [Suggest Awesome GitHub Copilot Chatmodes](prompts/suggest-awesome-github-copilot-chatmodes.prompt.md) | Suggest relevant GitHub Copilot chatmode files from the awesome-copilot repository based on current repository context and chat history, avoiding duplicates with existing chatmodes in this repository. | [![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://vscode.dev/redirect?url=vscode%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fsuggest-awesome-github-copilot-chatmodes.prompt.md) [![Install in VS Code](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://insiders.vscode.dev/redirect?url=vscode-insiders%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fsuggest-awesome-github-copilot-chatmodes.prompt.md) | | [Suggest Awesome GitHub Copilot Prompts](prompts/suggest-awesome-github-copilot-prompts.prompt.md) | Suggest relevant GitHub Copilot prompt files from the awesome-copilot repository based on current repository context and chat history, avoiding duplicates with existing prompts in this repository. | [![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://vscode.dev/redirect?url=vscode%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fsuggest-awesome-github-copilot-prompts.prompt.md) [![Install in VS Code](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://insiders.vscode.dev/redirect?url=vscode-insiders%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fsuggest-awesome-github-copilot-prompts.prompt.md) | | [Update Azure Verified Modules in Bicep Files](prompts/update-avm-modules-in-bicep.prompt.md) | Update Azure Verified Modules (AVM) to latest versions in Bicep files. | [![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://vscode.dev/redirect?url=vscode%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fupdate-avm-modules-in-bicep.prompt.md) [![Install in VS Code](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://insiders.vscode.dev/redirect?url=vscode-insiders%3Achat-prompt%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Fprompts%2Fupdate-avm-modules-in-bicep.prompt.md) | diff --git a/prompts/postgresql-code-review.prompt.md b/prompts/postgresql-code-review.prompt.md new file mode 100644 index 0000000..19d2cca --- /dev/null +++ b/prompts/postgresql-code-review.prompt.md @@ -0,0 +1,213 @@ +--- +mode: 'agent' +tools: ['changes', 'codebase', 'editFiles', 'problems'] +description: 'PostgreSQL-specific code review focusing on PostgreSQL best practices, anti-patterns, and PostgreSQL-unique quality standards.' +--- + +# PostgreSQL Code Review Assistant + +Expert PostgreSQL code review for ${selection} (or entire project if no selection). Focus on PostgreSQL-specific best practices, anti-patterns, and quality standards that are unique to PostgreSQL. + +## ๐ŸŽฏ PostgreSQL-Specific Review Areas + +### JSONB Best Practices +```sql +-- โŒ BAD: Inefficient JSONB usage +SELECT * FROM orders WHERE data->>'status' = 'shipped'; -- No index support + +-- โœ… GOOD: Indexable JSONB queries +CREATE INDEX idx_orders_status ON orders USING gin((data->'status')); +SELECT * FROM orders WHERE data @> '{"status": "shipped"}'; + +-- โŒ BAD: Deep nesting without consideration +UPDATE orders SET data = data || '{"shipping":{"tracking":{"number":"123"}}}'; + +-- โœ… GOOD: Structured JSONB with validation +ALTER TABLE orders ADD CONSTRAINT valid_status +CHECK (data->>'status' IN ('pending', 'shipped', 'delivered')); +``` + +### Array Operations Review +```sql +-- โŒ BAD: Inefficient array operations +SELECT * FROM products WHERE 'electronics' = ANY(categories); -- No index + +-- โœ… GOOD: GIN indexed array queries +CREATE INDEX idx_products_categories ON products USING gin(categories); +SELECT * FROM products WHERE categories @> ARRAY['electronics']; + +-- โŒ BAD: Array concatenation in loops +-- This would be inefficient in a function/procedure + +-- โœ… GOOD: Bulk array operations +UPDATE products SET categories = categories || ARRAY['new_category'] +WHERE id IN (SELECT id FROM products WHERE condition); +``` + +### PostgreSQL Schema Design Review +```sql +-- โŒ BAD: Not using PostgreSQL features +CREATE TABLE users ( + id INTEGER, + email VARCHAR(255), + created_at TIMESTAMP +); + +-- โœ… GOOD: PostgreSQL-optimized schema +CREATE TABLE users ( + id BIGSERIAL PRIMARY KEY, + email CITEXT UNIQUE NOT NULL, -- Case-insensitive email + created_at TIMESTAMPTZ DEFAULT NOW(), + metadata JSONB DEFAULT '{}', + CONSTRAINT valid_email CHECK (email ~* '^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}$') +); + +-- Add JSONB GIN index for metadata queries +CREATE INDEX idx_users_metadata ON users USING gin(metadata); +``` + +### Custom Types and Domains +```sql +-- โŒ BAD: Using generic types for specific data +CREATE TABLE transactions ( + amount DECIMAL(10,2), + currency VARCHAR(3), + status VARCHAR(20) +); + +-- โœ… GOOD: PostgreSQL custom types +CREATE TYPE currency_code AS ENUM ('USD', 'EUR', 'GBP', 'JPY'); +CREATE TYPE transaction_status AS ENUM ('pending', 'completed', 'failed', 'cancelled'); +CREATE DOMAIN positive_amount AS DECIMAL(10,2) CHECK (VALUE > 0); + +CREATE TABLE transactions ( + amount positive_amount NOT NULL, + currency currency_code NOT NULL, + status transaction_status DEFAULT 'pending' +); +``` + +## ๐Ÿ” PostgreSQL-Specific Anti-Patterns + +### Performance Anti-Patterns +- **Avoiding PostgreSQL-specific indexes**: Not using GIN/GiST for appropriate data types +- **Misusing JSONB**: Treating JSONB like a simple string field +- **Ignoring array operators**: Using inefficient array operations +- **Poor partition key selection**: Not leveraging PostgreSQL partitioning effectively + +### Schema Design Issues +- **Not using ENUM types**: Using VARCHAR for limited value sets +- **Ignoring constraints**: Missing CHECK constraints for data validation +- **Wrong data types**: Using VARCHAR instead of TEXT or CITEXT +- **Missing JSONB structure**: Unstructured JSONB without validation + +### Function and Trigger Issues +```sql +-- โŒ BAD: Inefficient trigger function +CREATE OR REPLACE FUNCTION update_modified_time() +RETURNS TRIGGER AS $$ +BEGIN + NEW.updated_at = NOW(); -- Should use TIMESTAMPTZ + RETURN NEW; +END; +$$ LANGUAGE plpgsql; + +-- โœ… GOOD: Optimized trigger function +CREATE OR REPLACE FUNCTION update_modified_time() +RETURNS TRIGGER AS $$ +BEGIN + NEW.updated_at = CURRENT_TIMESTAMP; + RETURN NEW; +END; +$$ LANGUAGE plpgsql; + +-- Set trigger to fire only when needed +CREATE TRIGGER update_modified_time_trigger + BEFORE UPDATE ON table_name + FOR EACH ROW + WHEN (OLD.* IS DISTINCT FROM NEW.*) + EXECUTE FUNCTION update_modified_time(); +``` + +## ๐Ÿ“Š PostgreSQL Extension Usage Review + +### Extension Best Practices +```sql +-- โœ… Check if extension exists before creating +CREATE EXTENSION IF NOT EXISTS "uuid-ossp"; +CREATE EXTENSION IF NOT EXISTS "pgcrypto"; +CREATE EXTENSION IF NOT EXISTS "pg_trgm"; + +-- โœ… Use extensions appropriately +-- UUID generation +SELECT uuid_generate_v4(); + +-- Password hashing +SELECT crypt('password', gen_salt('bf')); + +-- Fuzzy text matching +SELECT word_similarity('postgres', 'postgre'); +``` + +## ๐Ÿ›ก๏ธ PostgreSQL Security Review + +### Row Level Security (RLS) +```sql +-- โœ… GOOD: Implementing RLS +ALTER TABLE sensitive_data ENABLE ROW LEVEL SECURITY; + +CREATE POLICY user_data_policy ON sensitive_data + FOR ALL TO application_role + USING (user_id = current_setting('app.current_user_id')::INTEGER); +``` + +### Privilege Management +```sql +-- โŒ BAD: Overly broad permissions +GRANT ALL PRIVILEGES ON ALL TABLES IN SCHEMA public TO app_user; + +-- โœ… GOOD: Granular permissions +GRANT SELECT, INSERT, UPDATE ON specific_table TO app_user; +GRANT USAGE ON SEQUENCE specific_table_id_seq TO app_user; +``` + +## ๐ŸŽฏ PostgreSQL Code Quality Checklist + +### Schema Design +- [ ] Using appropriate PostgreSQL data types (CITEXT, JSONB, arrays) +- [ ] Leveraging ENUM types for constrained values +- [ ] Implementing proper CHECK constraints +- [ ] Using TIMESTAMPTZ instead of TIMESTAMP +- [ ] Defining custom domains for reusable constraints + +### Performance Considerations +- [ ] Appropriate index types (GIN for JSONB/arrays, GiST for ranges) +- [ ] JSONB queries using containment operators (@>, ?) +- [ ] Array operations using PostgreSQL-specific operators +- [ ] Proper use of window functions and CTEs +- [ ] Efficient use of PostgreSQL-specific functions + +### PostgreSQL Features Utilization +- [ ] Using extensions where appropriate +- [ ] Implementing stored procedures in PL/pgSQL when beneficial +- [ ] Leveraging PostgreSQL's advanced SQL features +- [ ] Using PostgreSQL-specific optimization techniques +- [ ] Implementing proper error handling in functions + +### Security and Compliance +- [ ] Row Level Security (RLS) implementation where needed +- [ ] Proper role and privilege management +- [ ] Using PostgreSQL's built-in encryption functions +- [ ] Implementing audit trails with PostgreSQL features + +## ๐Ÿ“ PostgreSQL-Specific Review Guidelines + +1. **Data Type Optimization**: Ensure PostgreSQL-specific types are used appropriately +2. **Index Strategy**: Review index types and ensure PostgreSQL-specific indexes are utilized +3. **JSONB Structure**: Validate JSONB schema design and query patterns +4. **Function Quality**: Review PL/pgSQL functions for efficiency and best practices +5. **Extension Usage**: Verify appropriate use of PostgreSQL extensions +6. **Performance Features**: Check utilization of PostgreSQL's advanced features +7. **Security Implementation**: Review PostgreSQL-specific security features + +Focus on PostgreSQL's unique capabilities and ensure the code leverages what makes PostgreSQL special rather than treating it as a generic SQL database. diff --git a/prompts/postgresql-optimization.prompt.md b/prompts/postgresql-optimization.prompt.md new file mode 100644 index 0000000..7754323 --- /dev/null +++ b/prompts/postgresql-optimization.prompt.md @@ -0,0 +1,405 @@ +--- +mode: 'agent' +tools: ['changes', 'codebase', 'editFiles', 'problems'] +description: 'PostgreSQL-specific development assistant focusing on unique PostgreSQL features, advanced data types, and PostgreSQL-exclusive capabilities. Complements general SQL optimization and code review.' +--- + +# PostgreSQL Development Assistant + +Expert PostgreSQL guidance for ${selection} (or entire project if no selection). Focus on PostgreSQL-specific features, optimization patterns, and advanced capabilities. + +## ๏ฟฝ PostgreSQL-Specific Features + +### JSONB Operations +```sql +-- Advanced JSONB queries +CREATE TABLE events ( + id SERIAL PRIMARY KEY, + data JSONB NOT NULL, + created_at TIMESTAMPTZ DEFAULT NOW() +); + +-- GIN index for JSONB performance +CREATE INDEX idx_events_data_gin ON events USING gin(data); + +-- JSONB containment and path queries +SELECT * FROM events +WHERE data @> '{"type": "login"}' + AND data #>> '{user,role}' = 'admin'; + +-- JSONB aggregation +SELECT jsonb_agg(data) FROM events WHERE data ? 'user_id'; +``` + +### Array Operations +```sql +-- PostgreSQL arrays +CREATE TABLE posts ( + id SERIAL PRIMARY KEY, + tags TEXT[], + categories INTEGER[] +); + +-- Array queries and operations +SELECT * FROM posts WHERE 'postgresql' = ANY(tags); +SELECT * FROM posts WHERE tags && ARRAY['database', 'sql']; +SELECT * FROM posts WHERE array_length(tags, 1) > 3; + +-- Array aggregation +SELECT array_agg(DISTINCT category) FROM posts, unnest(categories) as category; +``` + +### Window Functions & Analytics +```sql +-- Advanced window functions +SELECT + product_id, + sale_date, + amount, + -- Running totals + SUM(amount) OVER (PARTITION BY product_id ORDER BY sale_date) as running_total, + -- Moving averages + AVG(amount) OVER (PARTITION BY product_id ORDER BY sale_date ROWS BETWEEN 2 PRECEDING AND CURRENT ROW) as moving_avg, + -- Rankings + DENSE_RANK() OVER (PARTITION BY EXTRACT(month FROM sale_date) ORDER BY amount DESC) as monthly_rank, + -- Lag/Lead for comparisons + LAG(amount, 1) OVER (PARTITION BY product_id ORDER BY sale_date) as prev_amount +FROM sales; +``` + +### Full-Text Search +```sql +-- PostgreSQL full-text search +CREATE TABLE documents ( + id SERIAL PRIMARY KEY, + title TEXT, + content TEXT, + search_vector tsvector +); + +-- Update search vector +UPDATE documents +SET search_vector = to_tsvector('english', title || ' ' || content); + +-- GIN index for search performance +CREATE INDEX idx_documents_search ON documents USING gin(search_vector); + +-- Search queries +SELECT * FROM documents +WHERE search_vector @@ plainto_tsquery('english', 'postgresql database'); + +-- Ranking results +SELECT *, ts_rank(search_vector, plainto_tsquery('postgresql')) as rank +FROM documents +WHERE search_vector @@ plainto_tsquery('postgresql') +ORDER BY rank DESC; +``` + +## ๏ฟฝ PostgreSQL Performance Tuning + +### Query Optimization +```sql +-- EXPLAIN ANALYZE for performance analysis +EXPLAIN (ANALYZE, BUFFERS, FORMAT TEXT) +SELECT u.name, COUNT(o.id) as order_count +FROM users u +LEFT JOIN orders o ON u.id = o.user_id +WHERE u.created_at > '2024-01-01'::date +GROUP BY u.id, u.name; + +-- Identify slow queries from pg_stat_statements +SELECT query, calls, total_time, mean_time, rows, + 100.0 * shared_blks_hit / nullif(shared_blks_hit + shared_blks_read, 0) AS hit_percent +FROM pg_stat_statements +ORDER BY total_time DESC +LIMIT 10; +``` + +### Index Strategies +```sql +-- Composite indexes for multi-column queries +CREATE INDEX idx_orders_user_date ON orders(user_id, order_date); + +-- Partial indexes for filtered queries +CREATE INDEX idx_active_users ON users(created_at) WHERE status = 'active'; + +-- Expression indexes for computed values +CREATE INDEX idx_users_lower_email ON users(lower(email)); + +-- Covering indexes to avoid table lookups +CREATE INDEX idx_orders_covering ON orders(user_id, status) INCLUDE (total, created_at); +``` + +### Connection & Memory Management +```sql +-- Check connection usage +SELECT count(*) as connections, state +FROM pg_stat_activity +GROUP BY state; + +-- Monitor memory usage +SELECT name, setting, unit +FROM pg_settings +WHERE name IN ('shared_buffers', 'work_mem', 'maintenance_work_mem'); +``` + +## ๏ฟฝ๏ธ PostgreSQL Advanced Data Types + +### Custom Types & Domains +```sql +-- Create custom types +CREATE TYPE address_type AS ( + street TEXT, + city TEXT, + postal_code TEXT, + country TEXT +); + +CREATE TYPE order_status AS ENUM ('pending', 'processing', 'shipped', 'delivered', 'cancelled'); + +-- Use domains for data validation +CREATE DOMAIN email_address AS TEXT +CHECK (VALUE ~* '^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}$'); + +-- Table using custom types +CREATE TABLE customers ( + id SERIAL PRIMARY KEY, + email email_address NOT NULL, + address address_type, + status order_status DEFAULT 'pending' +); +``` + +### Range Types +```sql +-- PostgreSQL range types +CREATE TABLE reservations ( + id SERIAL PRIMARY KEY, + room_id INTEGER, + reservation_period tstzrange, + price_range numrange +); + +-- Range queries +SELECT * FROM reservations +WHERE reservation_period && tstzrange('2024-07-20', '2024-07-25'); + +-- Exclude overlapping ranges +ALTER TABLE reservations +ADD CONSTRAINT no_overlap +EXCLUDE USING gist (room_id WITH =, reservation_period WITH &&); +``` + +### Geometric Types +```sql +-- PostgreSQL geometric types +CREATE TABLE locations ( + id SERIAL PRIMARY KEY, + name TEXT, + coordinates POINT, + coverage CIRCLE, + service_area POLYGON +); + +-- Geometric queries +SELECT name FROM locations +WHERE coordinates <-> point(40.7128, -74.0060) < 10; -- Within 10 units + +-- GiST index for geometric data +CREATE INDEX idx_locations_coords ON locations USING gist(coordinates); +``` + +## ๐Ÿ“Š PostgreSQL Extensions & Tools + +### Useful Extensions +```sql +-- Enable commonly used extensions +CREATE EXTENSION IF NOT EXISTS "uuid-ossp"; -- UUID generation +CREATE EXTENSION IF NOT EXISTS "pgcrypto"; -- Cryptographic functions +CREATE EXTENSION IF NOT EXISTS "unaccent"; -- Remove accents from text +CREATE EXTENSION IF NOT EXISTS "pg_trgm"; -- Trigram matching +CREATE EXTENSION IF NOT EXISTS "btree_gin"; -- GIN indexes for btree types + +-- Using extensions +SELECT uuid_generate_v4(); -- Generate UUIDs +SELECT crypt('password', gen_salt('bf')); -- Hash passwords +SELECT similarity('postgresql', 'postgersql'); -- Fuzzy matching +``` + +### Monitoring & Maintenance +```sql +-- Database size and growth +SELECT pg_size_pretty(pg_database_size(current_database())) as db_size; + +-- Table and index sizes +SELECT schemaname, tablename, + pg_size_pretty(pg_total_relation_size(schemaname||'.'||tablename)) as size +FROM pg_tables +ORDER BY pg_total_relation_size(schemaname||'.'||tablename) DESC; + +-- Index usage statistics +SELECT schemaname, tablename, indexname, idx_scan, idx_tup_read, idx_tup_fetch +FROM pg_stat_user_indexes +WHERE idx_scan = 0; -- Unused indexes +``` + +### PostgreSQL-Specific Optimization Tips +- **Use EXPLAIN (ANALYZE, BUFFERS)** for detailed query analysis +- **Configure postgresql.conf** for your workload (OLTP vs OLAP) +- **Use connection pooling** (pgbouncer) for high-concurrency applications +- **Regular VACUUM and ANALYZE** for optimal performance +- **Partition large tables** using PostgreSQL 10+ declarative partitioning +- **Use pg_stat_statements** for query performance monitoring + +## ๐Ÿ“Š Monitoring and Maintenance + +### Query Performance Monitoring +```sql +-- Identify slow queries +SELECT query, calls, total_time, mean_time, rows +FROM pg_stat_statements +ORDER BY total_time DESC +LIMIT 10; + +-- Check index usage +SELECT schemaname, tablename, indexname, idx_scan, idx_tup_read, idx_tup_fetch +FROM pg_stat_user_indexes +WHERE idx_scan = 0; +``` + +### Database Maintenance +- **VACUUM and ANALYZE**: Regular maintenance for performance +- **Index Maintenance**: Monitor and rebuild fragmented indexes +- **Statistics Updates**: Keep query planner statistics current +- **Log Analysis**: Regular review of PostgreSQL logs + +## ๐Ÿ› ๏ธ Common Query Patterns + +### Pagination +```sql +-- โŒ BAD: OFFSET for large datasets +SELECT * FROM products ORDER BY id OFFSET 10000 LIMIT 20; + +-- โœ… GOOD: Cursor-based pagination +SELECT * FROM products +WHERE id > $last_id +ORDER BY id +LIMIT 20; +``` + +### Aggregation +```sql +-- โŒ BAD: Inefficient grouping +SELECT user_id, COUNT(*) +FROM orders +WHERE order_date >= '2024-01-01' +GROUP BY user_id; + +-- โœ… GOOD: Optimized with partial index +CREATE INDEX idx_orders_recent ON orders(user_id) +WHERE order_date >= '2024-01-01'; + +SELECT user_id, COUNT(*) +FROM orders +WHERE order_date >= '2024-01-01' +GROUP BY user_id; +``` + +### JSON Queries +```sql +-- โŒ BAD: Inefficient JSON querying +SELECT * FROM users WHERE data::text LIKE '%admin%'; + +-- โœ… GOOD: JSONB operators and GIN index +CREATE INDEX idx_users_data_gin ON users USING gin(data); + +SELECT * FROM users WHERE data @> '{"role": "admin"}'; +``` + +## ๐Ÿ“‹ Optimization Checklist + +### Query Analysis +- [ ] Run EXPLAIN ANALYZE for expensive queries +- [ ] Check for sequential scans on large tables +- [ ] Verify appropriate join algorithms +- [ ] Review WHERE clause selectivity +- [ ] Analyze sort and aggregation operations + +### Index Strategy +- [ ] Create indexes for frequently queried columns +- [ ] Use composite indexes for multi-column searches +- [ ] Consider partial indexes for filtered queries +- [ ] Remove unused or duplicate indexes +- [ ] Monitor index bloat and fragmentation + +### Security Review +- [ ] Use parameterized queries exclusively +- [ ] Implement proper access controls +- [ ] Enable row-level security where needed +- [ ] Audit sensitive data access +- [ ] Use secure connection methods + +### Performance Monitoring +- [ ] Set up query performance monitoring +- [ ] Configure appropriate log settings +- [ ] Monitor connection pool usage +- [ ] Track database growth and maintenance needs +- [ ] Set up alerting for performance degradation + +## ๐ŸŽฏ Optimization Output Format + +### Query Analysis Results +``` +## Query Performance Analysis + +**Original Query**: +[Original SQL with performance issues] + +**Issues Identified**: +- Sequential scan on large table (Cost: 15000.00) +- Missing index on frequently queried column +- Inefficient join order + +**Optimized Query**: +[Improved SQL with explanations] + +**Recommended Indexes**: +```sql +CREATE INDEX idx_table_column ON table(column); +``` + +**Performance Impact**: Expected 80% improvement in execution time +``` + +## ๐Ÿš€ Advanced PostgreSQL Features + +### Window Functions +```sql +-- Running totals and rankings +SELECT + product_id, + order_date, + amount, + SUM(amount) OVER (PARTITION BY product_id ORDER BY order_date) as running_total, + ROW_NUMBER() OVER (PARTITION BY product_id ORDER BY amount DESC) as rank +FROM sales; +``` + +### Common Table Expressions (CTEs) +```sql +-- Recursive queries for hierarchical data +WITH RECURSIVE category_tree AS ( + SELECT id, name, parent_id, 1 as level + FROM categories + WHERE parent_id IS NULL + + UNION ALL + + SELECT c.id, c.name, c.parent_id, ct.level + 1 + FROM categories c + JOIN category_tree ct ON c.parent_id = ct.id +) +SELECT * FROM category_tree ORDER BY level, name; +``` + +Focus on providing specific, actionable PostgreSQL optimizations that improve query performance, security, and maintainability while leveraging PostgreSQL's advanced features. diff --git a/prompts/sql-code-review.prompt.md b/prompts/sql-code-review.prompt.md new file mode 100644 index 0000000..bebab0a --- /dev/null +++ b/prompts/sql-code-review.prompt.md @@ -0,0 +1,302 @@ +--- +mode: 'agent' +tools: ['changes', 'codebase', 'editFiles', 'problems'] +description: 'Universal SQL code review focusing on security, maintainability, and code quality standards across all SQL databases. Complements SQL optimization prompt.' +--- + +# SQL Code Review + +Perform a thorough SQL code review of ${selection} (or entire project if no selection) focusing on security, performance, maintainability, and database best practices. + +## ๐Ÿ”’ Security Analysis + +### SQL Injection Prevention +```sql +-- โŒ CRITICAL: SQL Injection vulnerability +query = "SELECT * FROM users WHERE id = " + userInput; +query = f"DELETE FROM orders WHERE user_id = {user_id}"; + +-- โœ… SECURE: Parameterized queries +-- PostgreSQL/MySQL +PREPARE stmt FROM 'SELECT * FROM users WHERE id = ?'; +EXECUTE stmt USING @user_id; + +-- SQL Server +EXEC sp_executesql N'SELECT * FROM users WHERE id = @id', N'@id INT', @id = @user_id; +``` + +### Access Control & Permissions +- **Principle of Least Privilege**: Grant minimum required permissions +- **Role-Based Access**: Use database roles instead of direct user permissions +- **Schema Security**: Proper schema ownership and access controls +- **Function/Procedure Security**: Review DEFINER vs INVOKER rights + +### Data Protection +- **Sensitive Data Exposure**: Avoid SELECT * on tables with sensitive columns +- **Audit Logging**: Ensure sensitive operations are logged +- **Data Masking**: Use views or functions to mask sensitive data +- **Encryption**: Verify encrypted storage for sensitive data + +## โšก Performance Optimization + +### Query Structure Analysis +```sql +-- โŒ BAD: Inefficient query patterns +SELECT DISTINCT u.* +FROM users u, orders o, products p +WHERE u.id = o.user_id +AND o.product_id = p.id +AND YEAR(o.order_date) = 2024; + +-- โœ… GOOD: Optimized structure +SELECT u.id, u.name, u.email +FROM users u +INNER JOIN orders o ON u.id = o.user_id +WHERE o.order_date >= '2024-01-01' +AND o.order_date < '2025-01-01'; +``` + +### Index Strategy Review +- **Missing Indexes**: Identify columns that need indexing +- **Over-Indexing**: Find unused or redundant indexes +- **Composite Indexes**: Multi-column indexes for complex queries +- **Index Maintenance**: Check for fragmented or outdated indexes + +### Join Optimization +- **Join Types**: Verify appropriate join types (INNER vs LEFT vs EXISTS) +- **Join Order**: Optimize for smaller result sets first +- **Cartesian Products**: Identify and fix missing join conditions +- **Subquery vs JOIN**: Choose the most efficient approach + +### Aggregate and Window Functions +```sql +-- โŒ BAD: Inefficient aggregation +SELECT user_id, + (SELECT COUNT(*) FROM orders o2 WHERE o2.user_id = o1.user_id) as order_count +FROM orders o1 +GROUP BY user_id; + +-- โœ… GOOD: Efficient aggregation +SELECT user_id, COUNT(*) as order_count +FROM orders +GROUP BY user_id; +``` + +## ๐Ÿ› ๏ธ Code Quality & Maintainability + +### SQL Style & Formatting +```sql +-- โŒ BAD: Poor formatting and style +select u.id,u.name,o.total from users u left join orders o on u.id=o.user_id where u.status='active' and o.order_date>='2024-01-01'; + +-- โœ… GOOD: Clean, readable formatting +SELECT u.id, + u.name, + o.total +FROM users u +LEFT JOIN orders o ON u.id = o.user_id +WHERE u.status = 'active' + AND o.order_date >= '2024-01-01'; +``` + +### Naming Conventions +- **Consistent Naming**: Tables, columns, constraints follow consistent patterns +- **Descriptive Names**: Clear, meaningful names for database objects +- **Reserved Words**: Avoid using database reserved words as identifiers +- **Case Sensitivity**: Consistent case usage across schema + +### Schema Design Review +- **Normalization**: Appropriate normalization level (avoid over/under-normalization) +- **Data Types**: Optimal data type choices for storage and performance +- **Constraints**: Proper use of PRIMARY KEY, FOREIGN KEY, CHECK, NOT NULL +- **Default Values**: Appropriate default values for columns + +## ๐Ÿ—„๏ธ Database-Specific Best Practices + +### PostgreSQL +```sql +-- Use JSONB for JSON data +CREATE TABLE events ( + id SERIAL PRIMARY KEY, + data JSONB NOT NULL, + created_at TIMESTAMPTZ DEFAULT NOW() +); + +-- GIN index for JSONB queries +CREATE INDEX idx_events_data ON events USING gin(data); + +-- Array types for multi-value columns +CREATE TABLE tags ( + post_id INT, + tag_names TEXT[] +); +``` + +### MySQL +```sql +-- Use appropriate storage engines +CREATE TABLE sessions ( + id VARCHAR(128) PRIMARY KEY, + data TEXT, + expires TIMESTAMP +) ENGINE=InnoDB; + +-- Optimize for InnoDB +ALTER TABLE large_table +ADD INDEX idx_covering (status, created_at, id); +``` + +### SQL Server +```sql +-- Use appropriate data types +CREATE TABLE products ( + id BIGINT IDENTITY(1,1) PRIMARY KEY, + name NVARCHAR(255) NOT NULL, + price DECIMAL(10,2) NOT NULL, + created_at DATETIME2 DEFAULT GETUTCDATE() +); + +-- Columnstore indexes for analytics +CREATE COLUMNSTORE INDEX idx_sales_cs ON sales; +``` + +### Oracle +```sql +-- Use sequences for auto-increment +CREATE SEQUENCE user_id_seq START WITH 1 INCREMENT BY 1; + +CREATE TABLE users ( + id NUMBER DEFAULT user_id_seq.NEXTVAL PRIMARY KEY, + name VARCHAR2(255) NOT NULL +); +``` + +## ๐Ÿงช Testing & Validation + +### Data Integrity Checks +```sql +-- Verify referential integrity +SELECT o.user_id +FROM orders o +LEFT JOIN users u ON o.user_id = u.id +WHERE u.id IS NULL; + +-- Check for data consistency +SELECT COUNT(*) as inconsistent_records +FROM products +WHERE price < 0 OR stock_quantity < 0; +``` + +### Performance Testing +- **Execution Plans**: Review query execution plans +- **Load Testing**: Test queries with realistic data volumes +- **Stress Testing**: Verify performance under concurrent load +- **Regression Testing**: Ensure optimizations don't break functionality + +## ๐Ÿ“Š Common Anti-Patterns + +### N+1 Query Problem +```sql +-- โŒ BAD: N+1 queries in application code +for user in users: + orders = query("SELECT * FROM orders WHERE user_id = ?", user.id) + +-- โœ… GOOD: Single optimized query +SELECT u.*, o.* +FROM users u +LEFT JOIN orders o ON u.id = o.user_id; +``` + +### Overuse of DISTINCT +```sql +-- โŒ BAD: DISTINCT masking join issues +SELECT DISTINCT u.name +FROM users u, orders o +WHERE u.id = o.user_id; + +-- โœ… GOOD: Proper join without DISTINCT +SELECT u.name +FROM users u +INNER JOIN orders o ON u.id = o.user_id +GROUP BY u.name; +``` + +### Function Misuse in WHERE Clauses +```sql +-- โŒ BAD: Functions prevent index usage +SELECT * FROM orders +WHERE YEAR(order_date) = 2024; + +-- โœ… GOOD: Range conditions use indexes +SELECT * FROM orders +WHERE order_date >= '2024-01-01' + AND order_date < '2025-01-01'; +``` + +## ๐Ÿ“‹ SQL Review Checklist + +### Security +- [ ] All user inputs are parameterized +- [ ] No dynamic SQL construction with string concatenation +- [ ] Appropriate access controls and permissions +- [ ] Sensitive data is properly protected +- [ ] SQL injection attack vectors are eliminated + +### Performance +- [ ] Indexes exist for frequently queried columns +- [ ] No unnecessary SELECT * statements +- [ ] JOINs are optimized and use appropriate types +- [ ] WHERE clauses are selective and use indexes +- [ ] Subqueries are optimized or converted to JOINs + +### Code Quality +- [ ] Consistent naming conventions +- [ ] Proper formatting and indentation +- [ ] Meaningful comments for complex logic +- [ ] Appropriate data types are used +- [ ] Error handling is implemented + +### Schema Design +- [ ] Tables are properly normalized +- [ ] Constraints enforce data integrity +- [ ] Indexes support query patterns +- [ ] Foreign key relationships are defined +- [ ] Default values are appropriate + +## ๐ŸŽฏ Review Output Format + +### Issue Template +``` +## [PRIORITY] [CATEGORY]: [Brief Description] + +**Location**: [Table/View/Procedure name and line number if applicable] +**Issue**: [Detailed explanation of the problem] +**Security Risk**: [If applicable - injection risk, data exposure, etc.] +**Performance Impact**: [Query cost, execution time impact] +**Recommendation**: [Specific fix with code example] + +**Before**: +```sql +-- Problematic SQL +``` + +**After**: +```sql +-- Improved SQL +``` + +**Expected Improvement**: [Performance gain, security benefit] +``` + +### Summary Assessment +- **Security Score**: [1-10] - SQL injection protection, access controls +- **Performance Score**: [1-10] - Query efficiency, index usage +- **Maintainability Score**: [1-10] - Code quality, documentation +- **Schema Quality Score**: [1-10] - Design patterns, normalization + +### Top 3 Priority Actions +1. **[Critical Security Fix]**: Address SQL injection vulnerabilities +2. **[Performance Optimization]**: Add missing indexes or optimize queries +3. **[Code Quality]**: Improve naming conventions and documentation + +Focus on providing actionable, database-agnostic recommendations while highlighting platform-specific optimizations and best practices. diff --git a/prompts/sql-optimization.prompt.md b/prompts/sql-optimization.prompt.md new file mode 100644 index 0000000..3906799 --- /dev/null +++ b/prompts/sql-optimization.prompt.md @@ -0,0 +1,297 @@ +--- +mode: 'agent' +tools: ['changes', 'codebase', 'editFiles', 'problems'] +description: 'Universal SQL performance optimization assistant for query tuning, indexing strategies, and database performance across all SQL databases.' +--- + +# SQL Performance Optimization Assistant + +Expert SQL performance optimization for ${selection} (or entire project if no selection). Focus on universal SQL optimization techniques that work across MySQL, PostgreSQL, SQL Server, Oracle, and other SQL databases. + +## ๐ŸŽฏ Core Optimization Areas + +### Query Performance Analysis +```sql +-- โŒ BAD: Inefficient query patterns +SELECT * FROM orders o +WHERE YEAR(o.created_at) = 2024 + AND o.customer_id IN ( + SELECT c.id FROM customers c WHERE c.status = 'active' + ); + +-- โœ… GOOD: Optimized query with proper indexing hints +SELECT o.id, o.customer_id, o.total_amount, o.created_at +FROM orders o +INNER JOIN customers c ON o.customer_id = c.id +WHERE o.created_at >= '2024-01-01' + AND o.created_at < '2025-01-01' + AND c.status = 'active'; + +-- Required indexes: +-- CREATE INDEX idx_orders_created_at ON orders(created_at); +-- CREATE INDEX idx_customers_status ON customers(status); +-- CREATE INDEX idx_orders_customer_id ON orders(customer_id); +``` + +### Index Strategy Optimization +```sql +-- โŒ BAD: Poor indexing strategy +CREATE INDEX idx_user_data ON users(email, first_name, last_name, created_at); + +-- โœ… GOOD: Optimized composite indexing +-- For queries filtering by email first, then sorting by created_at +CREATE INDEX idx_users_email_created ON users(email, created_at); + +-- For full-text name searches +CREATE INDEX idx_users_name ON users(last_name, first_name); + +-- For user status queries +CREATE INDEX idx_users_status_created ON users(status, created_at) +WHERE status IS NOT NULL; +``` + +### Subquery Optimization +```sql +-- โŒ BAD: Correlated subquery +SELECT p.product_name, p.price +FROM products p +WHERE p.price > ( + SELECT AVG(price) + FROM products p2 + WHERE p2.category_id = p.category_id +); + +-- โœ… GOOD: Window function approach +SELECT product_name, price +FROM ( + SELECT product_name, price, + AVG(price) OVER (PARTITION BY category_id) as avg_category_price + FROM products +) ranked +WHERE price > avg_category_price; +``` + +## ๐Ÿ“Š Performance Tuning Techniques + +### JOIN Optimization +```sql +-- โŒ BAD: Inefficient JOIN order and conditions +SELECT o.*, c.name, p.product_name +FROM orders o +LEFT JOIN customers c ON o.customer_id = c.id +LEFT JOIN order_items oi ON o.id = oi.order_id +LEFT JOIN products p ON oi.product_id = p.id +WHERE o.created_at > '2024-01-01' + AND c.status = 'active'; + +-- โœ… GOOD: Optimized JOIN with filtering +SELECT o.id, o.total_amount, c.name, p.product_name +FROM orders o +INNER JOIN customers c ON o.customer_id = c.id AND c.status = 'active' +INNER JOIN order_items oi ON o.id = oi.order_id +INNER JOIN products p ON oi.product_id = p.id +WHERE o.created_at > '2024-01-01'; +``` + +### Pagination Optimization +```sql +-- โŒ BAD: OFFSET-based pagination (slow for large offsets) +SELECT * FROM products +ORDER BY created_at DESC +LIMIT 20 OFFSET 10000; + +-- โœ… GOOD: Cursor-based pagination +SELECT * FROM products +WHERE created_at < '2024-06-15 10:30:00' +ORDER BY created_at DESC +LIMIT 20; + +-- Or using ID-based cursor +SELECT * FROM products +WHERE id > 1000 +ORDER BY id +LIMIT 20; +``` + +### Aggregation Optimization +```sql +-- โŒ BAD: Multiple separate aggregation queries +SELECT COUNT(*) FROM orders WHERE status = 'pending'; +SELECT COUNT(*) FROM orders WHERE status = 'shipped'; +SELECT COUNT(*) FROM orders WHERE status = 'delivered'; + +-- โœ… GOOD: Single query with conditional aggregation +SELECT + COUNT(CASE WHEN status = 'pending' THEN 1 END) as pending_count, + COUNT(CASE WHEN status = 'shipped' THEN 1 END) as shipped_count, + COUNT(CASE WHEN status = 'delivered' THEN 1 END) as delivered_count +FROM orders; +``` + +## ๐Ÿ” Query Anti-Patterns + +### SELECT Performance Issues +```sql +-- โŒ BAD: SELECT * anti-pattern +SELECT * FROM large_table lt +JOIN another_table at ON lt.id = at.ref_id; + +-- โœ… GOOD: Explicit column selection +SELECT lt.id, lt.name, at.value +FROM large_table lt +JOIN another_table at ON lt.id = at.ref_id; +``` + +### WHERE Clause Optimization +```sql +-- โŒ BAD: Function calls in WHERE clause +SELECT * FROM orders +WHERE UPPER(customer_email) = 'JOHN@EXAMPLE.COM'; + +-- โœ… GOOD: Index-friendly WHERE clause +SELECT * FROM orders +WHERE customer_email = 'john@example.com'; +-- Consider: CREATE INDEX idx_orders_email ON orders(LOWER(customer_email)); +``` + +### OR vs UNION Optimization +```sql +-- โŒ BAD: Complex OR conditions +SELECT * FROM products +WHERE (category = 'electronics' AND price < 1000) + OR (category = 'books' AND price < 50); + +-- โœ… GOOD: UNION approach for better optimization +SELECT * FROM products WHERE category = 'electronics' AND price < 1000 +UNION ALL +SELECT * FROM products WHERE category = 'books' AND price < 50; +``` + +## ๐Ÿ“ˆ Database-Agnostic Optimization + +### Batch Operations +```sql +-- โŒ BAD: Row-by-row operations +INSERT INTO products (name, price) VALUES ('Product 1', 10.00); +INSERT INTO products (name, price) VALUES ('Product 2', 15.00); +INSERT INTO products (name, price) VALUES ('Product 3', 20.00); + +-- โœ… GOOD: Batch insert +INSERT INTO products (name, price) VALUES +('Product 1', 10.00), +('Product 2', 15.00), +('Product 3', 20.00); +``` + +### Temporary Table Usage +```sql +-- โœ… GOOD: Using temporary tables for complex operations +CREATE TEMPORARY TABLE temp_calculations AS +SELECT customer_id, + SUM(total_amount) as total_spent, + COUNT(*) as order_count +FROM orders +WHERE created_at >= '2024-01-01' +GROUP BY customer_id; + +-- Use the temp table for further calculations +SELECT c.name, tc.total_spent, tc.order_count +FROM temp_calculations tc +JOIN customers c ON tc.customer_id = c.id +WHERE tc.total_spent > 1000; +``` + +## ๐Ÿ› ๏ธ Index Management + +### Index Design Principles +```sql +-- โœ… GOOD: Covering index design +CREATE INDEX idx_orders_covering +ON orders(customer_id, created_at) +INCLUDE (total_amount, status); -- SQL Server syntax +-- Or: CREATE INDEX idx_orders_covering ON orders(customer_id, created_at, total_amount, status); -- Other databases +``` + +### Partial Index Strategy +```sql +-- โœ… GOOD: Partial indexes for specific conditions +CREATE INDEX idx_orders_active +ON orders(created_at) +WHERE status IN ('pending', 'processing'); +``` + +## ๐Ÿ“Š Performance Monitoring Queries + +### Query Performance Analysis +```sql +-- Generic approach to identify slow queries +-- (Specific syntax varies by database) + +-- For MySQL: +SELECT query_time, lock_time, rows_sent, rows_examined, sql_text +FROM mysql.slow_log +ORDER BY query_time DESC; + +-- For PostgreSQL: +SELECT query, calls, total_time, mean_time +FROM pg_stat_statements +ORDER BY total_time DESC; + +-- For SQL Server: +SELECT + qs.total_elapsed_time/qs.execution_count as avg_elapsed_time, + qs.execution_count, + SUBSTRING(qt.text, (qs.statement_start_offset/2)+1, + ((CASE qs.statement_end_offset WHEN -1 THEN DATALENGTH(qt.text) + ELSE qs.statement_end_offset END - qs.statement_start_offset)/2)+1) as query_text +FROM sys.dm_exec_query_stats qs +CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) qt +ORDER BY avg_elapsed_time DESC; +``` + +## ๐ŸŽฏ Universal Optimization Checklist + +### Query Structure +- [ ] Avoiding SELECT * in production queries +- [ ] Using appropriate JOIN types (INNER vs LEFT/RIGHT) +- [ ] Filtering early in WHERE clauses +- [ ] Using EXISTS instead of IN for subqueries when appropriate +- [ ] Avoiding functions in WHERE clauses that prevent index usage + +### Index Strategy +- [ ] Creating indexes on frequently queried columns +- [ ] Using composite indexes in the right column order +- [ ] Avoiding over-indexing (impacts INSERT/UPDATE performance) +- [ ] Using covering indexes where beneficial +- [ ] Creating partial indexes for specific query patterns + +### Data Types and Schema +- [ ] Using appropriate data types for storage efficiency +- [ ] Normalizing appropriately (3NF for OLTP, denormalized for OLAP) +- [ ] Using constraints to help query optimizer +- [ ] Partitioning large tables when appropriate + +### Query Patterns +- [ ] Using LIMIT/TOP for result set control +- [ ] Implementing efficient pagination strategies +- [ ] Using batch operations for bulk data changes +- [ ] Avoiding N+1 query problems +- [ ] Using prepared statements for repeated queries + +### Performance Testing +- [ ] Testing queries with realistic data volumes +- [ ] Analyzing query execution plans +- [ ] Monitoring query performance over time +- [ ] Setting up alerts for slow queries +- [ ] Regular index usage analysis + +## ๐Ÿ“ Optimization Methodology + +1. **Identify**: Use database-specific tools to find slow queries +2. **Analyze**: Examine execution plans and identify bottlenecks +3. **Optimize**: Apply appropriate optimization techniques +4. **Test**: Verify performance improvements +5. **Monitor**: Continuously track performance metrics +6. **Iterate**: Regular performance review and optimization + +Focus on measurable performance improvements and always test optimizations with realistic data volumes and query patterns.