PostgreSQL database patterns for query optimization, schema design, indexing, and security. Based on Supabase best practices.
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PostgreSQL 最佳實務快速參考。詳細指南請使用 database-reviewer agent。
| 查詢模式 | 索引類型 | 範例 |
|---|---|---|
WHERE col = value | B-tree（預設） | CREATE INDEX idx ON t (col) |
WHERE col > value | B-tree | CREATE INDEX idx ON t (col) |
WHERE a = x AND b > y |
| 複合 |
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) |
| 時間序列範圍 | BRIN | CREATE INDEX idx ON t USING brin (col) |
| 使用情況 | 正確類型 | 避免 |
|---|---|---|
| IDs | bigint | int、隨機 UUID |
| 字串 | text | varchar(255) |
| 時間戳 | timestamptz | timestamp |
| 金額 | numeric(10,2) | float |
| 旗標 | boolean | varchar、int |
複合索引順序：
-- 等值欄位優先，然後是範圍欄位
CREATE INDEX idx ON orders (status, created_at);
-- 適用於：WHERE status = 'pending' AND created_at > '2024-01-01'
覆蓋索引：
CREATE INDEX idx ON users (email) INCLUDE (name, created_at);
-- 避免 SELECT email, name, created_at 時的表格查詢
部分索引：
CREATE INDEX idx ON users (email) WHERE deleted_at IS NULL;
-- 更小的索引，只包含活躍使用者
RLS 政策（優化）：
CREATE POLICY policy ON orders
USING ((SELECT auth.uid()) = user_id); -- 用 SELECT 包裝！
UPSERT：
INSERT INTO settings (user_id, key, value)
VALUES (123, 'theme', 'dark')
ON CONFLICT (user_id, key)
DO UPDATE SET value = EXCLUDED.value;
游標分頁：
SELECT * FROM products WHERE id > $last_id ORDER BY id LIMIT 20;
-- O(1) vs OFFSET 是 O(n)
佇列處理：
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 *;
-- 找出未建索引的外鍵
SELECT conrelid::regclass, a.attname
FROM pg_constraint c
JOIN 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)
);
-- 找出慢查詢
SELECT query, mean_exec_time, calls
FROM pg_stat_statements
WHERE mean_exec_time > 100
ORDER BY mean_exec_time DESC;
-- 檢查表格膨脹
SELECT relname, n_dead_tup, last_vacuum
FROM pg_stat_user_tables
WHERE n_dead_tup > 1000
ORDER BY n_dead_tup DESC;
-- 連線限制（依 RAM 調整）
ALTER SYSTEM SET max_connections = 100;
ALTER SYSTEM SET work_mem = '8MB';
-- 逾時
ALTER SYSTEM SET idle_in_transaction_session_timeout = '30s';
ALTER SYSTEM SET statement_timeout = '30s';
-- 監控
CREATE EXTENSION IF NOT EXISTS pg_stat_statements;
-- 安全預設值
REVOKE ALL ON SCHEMA public FROM public;
SELECT pg_reload_conf();
database-reviewer - 完整資料庫審查工作流程clickhouse-io - ClickHouse 分析模式backend-patterns - API 和後端模式基於 [Supabase Agent Skills](Supabase Agent Skills (credit: Supabase team))（MIT 授權）
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Create or update AgentSkills. Use when designing, structuring, or packaging skills with scripts, references, and assets.
Set up and use 1Password CLI (op). Use when installing the CLI, enabling desktop app integration, signing in (single or multi-account), or reading/injecting/running secrets via op.
CLI to manage emails via IMAP/SMTP. Use `himalaya` to list, read, write, reply, forward, search, and organize emails from the terminal. Supports multiple accounts and message composition with MML (MIME Meta Language).