浅谈django的db性能调优

from django.db import models

class UserInfo(models.Model):
    # 1. 基础字段
    username = models.CharField(max_length=50, unique=True)
    # 给 email 一个默认空字符串，或者设为 null=True，防止迁移报错
    email = models.EmailField(default='') 

    # 2. 状态字段
    status = models.SmallIntegerField(default=1, help_text="0:Inactive, 1:Active, 2:Banned")
    role = models.CharField(max_length=10, default='member')

    # 3. 数值字段
    age = models.PositiveSmallIntegerField(null=True)
    balance = models.DecimalField(max_digits=19, decimal_places=4, default=0.0000)
    score = models.IntegerField(default=0)

    # 4. 时间字段
    # 使用 auto_now_add=True 让 Django 自动处理创建时间
    created_at = models.DateTimeField(auto_now_add=True) 
    last_login = models.DateTimeField(null=True, blank=True)

    # 5. 大文本/复杂字段
    bio = models.TextField(null=True, blank=True)
    
    # 6. JSON 字段
    extras = models.JSONField(default=dict, null=True, blank=True)

    class Meta:
        db_table = 'user_demo'

python manage.py makemigration
python manage.py migrate

import os
import sys
import random
import string
import django

# 1. 设置 Django 环境
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
sys.path.append(BASE_DIR)
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "mysite.settings")
django.setup()

from main.models import UserInfo

def generate_random_string(length=10):
    """生成随机字符串"""
    letters = string.ascii_lowercase
    return ''.join(random.choice(letters) for i in range(length))

def create_demo_data(count=100):
    print(f"开始生成 {count} 条数据...")
    
    users = []
    # 预先定义好 choices，模拟真实数据分布
    ROLES = ['admin', 'editor', 'member', 'guest']
    
    for i in range(count):
        # 确保 username 唯一，这里简单加上索引 i
        username = f"user_{generate_random_string(5)}_{i}"
        
        user = UserInfo(
            username=username,
            email=f"{username}@example.com",
            status=random.choice([0, 1, 1, 1, 2]), # 1 的概率大一些
            role=random.choice(ROLES),
            age=random.randint(18, 80),
            balance=random.uniform(0, 100000),
            score=random.randint(0, 500000),
            bio=generate_random_string(500),
            extras={'preference': random.choice(['light', 'dark']), 'level': random.randint(1, 10)}
        )
        users.append(user)

    # bulk_create 一次性插入，性能更好
    UserInfo.objects.bulk_create(users)
    print(f"✅ 成功插入 {len(users)} 条数据到 UserInfo 表。")

if __name__ == "__main__":
    try:
        create_demo_data(1000000)
    except Exception as e:
        print(f"❌ 发生错误: {e}")

mysql> select count(*) from user_demo;
+----------+
| count(*) |
+----------+
|    10000 |
+----------+
1 row in set (0.002 sec)

import os
import sys
import random
import string
import django

# 1. 设置 Django 环境
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
sys.path.append(BASE_DIR)
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "mysite.settings")
django.setup()

from main.models import UserInfo

def generate_random_string(length=10):
    """生成随机字符串"""
    letters = string.ascii_lowercase
    return ''.join(random.choice(letters) for i in range(length))

def create_demo_data(count=100):
    print(f"开始生成 {count} 条数据...")
    
    users = []
    BATCH_SIZE = 5000  # 每次插入 5000 条
    # 预先定义好 choices，模拟真实数据分布
    ROLES = ['admin', 'editor', 'member', 'guest']
    batch_data = []
    for i in range(count):
        # 确保 username 唯一，这里简单加上索引 i
        username = f"user_{generate_random_string(5)}_{i}"
        
        user = UserInfo(
            username=username,
            email=f"{username}@example.com",
            status=random.choice([0, 1, 1, 1, 2]), # 1 的概率大一些
            role=random.choice(ROLES),
            age=random.randint(18, 80),
            balance=random.uniform(0, 100000),
            score=random.randint(0, 500000),
            bio=generate_random_string(500),
            extras={'preference': random.choice(['light', 'dark']), 'level': random.randint(1, 10)}
        )

        batch_data.append(user)
        # 当积攒够了 BATCH_SIZE，就插入一次
        if len(batch_data) >= BATCH_SIZE:
            UserInfo.objects.bulk_create(batch_data, batch_size=BATCH_SIZE)
            print(f"已插入 {i + 1} 条...")
            batch_data = [] # 清空列表

    # 插入剩余的数据（如果有的话）
    if batch_data:
        UserInfo.objects.bulk_create(batch_data)
        print(f"已插入剩余 {len(batch_data)} 条...")
    print(f"✅ 成功插入 {len(users)} 条数据到 UserInfo 表。")

if __name__ == "__main__":
    try:
        create_demo_data(1000000)
    except Exception as e:
        print(f"❌ 发生错误: {e}")

from main.models import UserInfo

users = UserInfo.objects.all()
users_usernames = [user.username for user in users]

from main.models import UserInfo

users_usernames = list(UserInfo.objects.values_list('username', flat=True))