PostgreSQL 模式
PostgreSQL 最佳实践快速参考。如需详细指导，请使用 database-reviewer 智能体。
何时激活
- 编写 SQL 查询或迁移时
- 设计数据库模式时
- 排查慢查询时
- 实施行级安全性时
- 设置连接池时
快速参考
索引速查表
| 查询模式 | 索引类型 | 示例 |
|---|---|---|
WHERE col = value | B-tree（默认） | CREATE INDEX idx ON t (col) |
WHERE col > value | B-tree | CREATE INDEX idx ON t (col) |
WHERE a = x AND b > y | 复合索引 | CREATE INDEX idx ON t (a, b) |
WHERE jsonb @> '{}' | GIN | CREATE INDEX idx ON t USING gin (col) |
WHERE tsv @@ query | GIN | CREATE INDEX idx ON t USING gin (col) |
| 时间序列范围查询 | BRIN | CREATE INDEX idx ON t USING brin (col) |
数据类型快速参考
| 使用场景 | 正确类型 | 避免使用 |
|---|---|---|
| ID | bigint | int，随机 UUID |
| 字符串 | text | varchar(255) |
| 时间戳 | timestamptz | timestamp |
| 货币 | numeric(10,2) | float |
| 标志位 | boolean | varchar，int |
常见模式
复合索引顺序：
sql
-- Equality columns first, then range columnsCREATE INDEX idx ON orders (status, created_at);-- Works for: WHERE status = 'pending' AND created_at > '2024-01-01'覆盖索引：
sql
CREATE INDEX idx ON users (email) INCLUDE (name, created_at);-- Avoids table lookup for SELECT email, name, created_at部分索引：
sql
CREATE INDEX idx ON users (email) WHERE deleted_at IS NULL;-- Smaller index, only includes active usersRLS 策略（优化版）：
sql
CREATE POLICY policy ON orders USING ((SELECT auth.uid()) = user_id); -- Wrap in SELECT!UPSERT：
sql
INSERT INTO settings (user_id, key, value)VALUES (123, 'theme', 'dark')ON CONFLICT (user_id, key)DO UPDATE SET value = EXCLUDED.value;游标分页：
sql
SELECT * FROM products WHERE id > $last_id ORDER BY id LIMIT 20;-- O(1) vs OFFSET which is O(n)队列处理：
sql
UPDATE jobs SET status = 'processing'WHERE id = ( SELECT id FROM jobs WHERE status = 'pending' ORDER BY created_at LIMIT 1 FOR UPDATE SKIP LOCKED) RETURNING *;反模式检测**
sql
-- Find unindexed foreign keysSELECT conrelid::regclass, a.attnameFROM pg_constraint cJOIN pg_attribute a ON a.attrelid = c.conrelid AND a.attnum = ANY(c.conkey)WHERE c.contype = 'f' AND NOT EXISTS ( SELECT 1 FROM pg_index i WHERE i.indrelid = c.conrelid AND a.attnum = ANY(i.indkey) );
-- Find slow queriesSELECT query, mean_exec_time, callsFROM pg_stat_statementsWHERE mean_exec_time > 100ORDER BY mean_exec_time DESC;
-- Check table bloatSELECT relname, n_dead_tup, last_vacuumFROM pg_stat_user_tablesWHERE n_dead_tup > 1000ORDER BY n_dead_tup DESC;配置模板
sql
-- Connection limits (adjust for RAM)ALTER SYSTEM SET max_connections = 100;ALTER SYSTEM SET work_mem = '8MB';
-- TimeoutsALTER SYSTEM SET idle_in_transaction_session_timeout = '30s';ALTER SYSTEM SET statement_timeout = '30s';
-- MonitoringCREATE EXTENSION IF NOT EXISTS pg_stat_statements;
-- Security defaultsREVOKE ALL ON SCHEMA public FROM public;
SELECT pg_reload_conf();相关
- 智能体：
database-reviewer- 完整的数据库审查工作流 - 技能：
clickhouse-io- ClickHouse 分析模式 - 技能：
backend-patterns- API 和后端模式
基于 Supabase 代理技能（致谢：Supabase 团队）（MIT 许可证）
