sudo apt update

sudo apt install postgresql postgresql-contrib

sudo systemctl status postgresql

sudo yum install -y postgresql-server postgresql-contrib
sudo postgresql-setup initdb
sudo systemctl enable postgresql
sudo systemctl start postgresql

listen_addresses = '*'

host    all             all             0.0.0.0/0               md5

sudo systemctl restart postgresql

port = 5432

sudo -i -u postgres

-- 創(chuàng)建用戶
CREATE USER myuser WITH PASSWORD 'mypassword';
-- 創(chuàng)建數(shù)據(jù)庫
CREATE DATABASE mydb OWNER myuser;
-- 授權
GRANT ALL PRIVILEGES ON DATABASE mydb TO myuser;

ALTER USER myuser WITH SUPERUSER;

psql -U myuser -h localhost -d mydb

-- 創(chuàng)建表
CREATE TABLE users (
    id SERIAL PRIMARY KEY,
    name VARCHAR(50),
    email VARCHAR(100)
);
-- 插入數(shù)據(jù)
INSERT INTO users (name, email) VALUES ('Alice', 'alice@example.com');
-- 查詢數(shù)據(jù)
SELECT * FROM users;
-- 更新數(shù)據(jù)
UPDATE users SET name = 'Bob' WHERE id = 1;
-- 刪除數(shù)據(jù)
DELETE FROM users WHERE id = 1;

pg_dump -U myuser -h localhost mydb > mydb_backup.sql

psql -U myuser -h localhost -d mydb < mydb_backup.sql

docker run --name some-postgres -e POSTGRES_PASSWORD=mysecretpassword -p 5432:5432 -d postgres

max_connections = 100          # 最大連接數(shù)
shared_buffers = 128MB         # 數(shù)據(jù)庫緩存區(qū)大小，建議為物理內存的 1/4
work_mem = 4MB                 # 每個查詢操作分配的內存
maintenance_work_mem = 64MB    # 維護操作（如 VACUUM）的內存
effective_cache_size = 512MB   # 操作系統(tǒng)可用于緩存的內存估算

logging_collector = on
log_directory = 'pg_log'
log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log'
log_statement = 'all'   # 建議生產環(huán)境設置為 'none' 或 'mod'

VACUUM;
VACUUM FULL;      -- 更徹底，可能會鎖表

CREATE INDEX idx_users_email ON users(email);

EXPLAIN SELECT * FROM users WHERE email = 'xxx';

CREATE TABLE measurement (
  city_id         int,
  logdate         date,
  peaktemp        int,
  unitsales       int
) PARTITION BY RANGE (logdate);

sudo apt install postgis
CREATE EXTENSION postgis;

CREATE EXTENSION "uuid-ossp";
SELECT uuid_generate_v4();

CREATE EXTENSION pg_stat_statements;
SELECT * FROM pg_stat_statements;

ssl = on
ssl_cert_file = 'server.crt'
ssl_key_file = 'server.key'

wal_level = replica
max_wal_senders = 10
archive_mode = on
archive_command = 'cp %p /var/lib/postgresql/wal_archive/%f'

host replication all <slave_ip>/32 md5

pg_basebackup -h <master_ip> -D /var/lib/postgresql/data -U replication -P --wal-method=stream

crontab -e

0 2 * * * pg_dump -U myuser -h localhost mydb > /backup/mydb_$(date +\%F).sql

find /backup/ -name "mydb_*.sql" -mtime +7 -exec rm {} \;

SELECT * FROM pg_stat_activity;
SELECT datname, numbackends, xact_commit, xact_rollback FROM pg_stat_database;

pg_dumpall -U postgres > all.sql
# 在新環(huán)境還原
psql -U postgres -f all.sql

INSERT INTO users (name, email)
VALUES
  ('Tom', 'tom@example.com'),
  ('Jerry', 'jerry@example.com'),
  ('Spike', 'spike@example.com');

UPDATE users SET status = 'active' WHERE id IN (1,2,3);

\d+ users

SELECT pg_size_pretty(pg_total_relation_size('users'));

SELECT count(*) FROM pg_stat_activity;

SELECT * FROM pg_locks WHERE NOT granted;

ALTER USER myuser WITH PASSWORD 'newpassword';

SELECT version();

pg_dump -U myuser -h localhost -s mydb > mydb_schema.sql

pg_dump -U myuser -h localhost -t users mydb > users.sql
psql -U myuser -d mydb < users.sql

CREATE TABLE sales (
    id serial PRIMARY KEY,
    sale_date date NOT NULL,
    amount numeric
) PARTITION BY RANGE (sale_date);
CREATE TABLE sales_2023 PARTITION OF sales FOR VALUES FROM ('2023-01-01') TO ('2024-01-01');
CREATE TABLE sales_2024 PARTITION OF sales FOR VALUES FROM ('2024-01-01') TO ('2025-01-01');

SELECT
    inhrelid::regclass AS child,
    inhparent::regclass AS parent
FROM
    pg_inherits;

BEGIN;
UPDATE users SET balance = balance - 100 WHERE id = 1;
UPDATE users SET balance = balance + 100 WHERE id = 2;
COMMIT;

SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;

SELECT * FROM pg_locks WHERE NOT granted;

CREATE TABLE users_log (
    id serial PRIMARY KEY,
    user_id int,
    action varchar(20),
    log_time timestamp DEFAULT now()
);
CREATE OR REPLACE FUNCTION log_user_update()
RETURNS trigger AS $$
BEGIN
    INSERT INTO users_log(user_id, action) VALUES (NEW.id, 'update');
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;
CREATE TRIGGER user_update_trig
AFTER UPDATE ON users
FOR EACH ROW EXECUTE FUNCTION log_user_update();

CREATE OR REPLACE FUNCTION add_user(name text, email text)
RETURNS void AS $$
BEGIN
    INSERT INTO users(name, email) VALUES (name, email);
END;
$$ LANGUAGE plpgsql;

SELECT add_user('Bob', 'bob@example.com');

CREATE TABLE orders (
    id serial PRIMARY KEY,
    info jsonb
);
INSERT INTO orders(info) VALUES ('{"customer": "Tom", "items": ["apple", "banana"]}');
SELECT info->>'customer' FROM orders;

CREATE TABLE docs (id serial PRIMARY KEY, content text);
INSERT INTO docs(content) VALUES ('PostgreSQL is a powerful database system.');
SELECT * FROM docs WHERE to_tsvector('english', content) @@ to_tsquery('powerful & database');

SELECT pg_terminate_backend(pid)
FROM pg_stat_activity
WHERE state = 'idle' AND pid <> pg_backend_pid();

REINDEX TABLE users;

SELECT relname, n_dead_tup
FROM pg_stat_user_tables
WHERE n_dead_tup > 1000;