Django - PostgreSQL 设置语句超时

Question

I'm using Django 1.10 and PostgreSQL DB. I'm trying to figure out whether I can set statement_timeout from Django. Seems like I can't do it the same way as for connect_timeout (in settings.py ):

DATABASES[DEFAULT]['OPTIONS'] = {
    'connect_timeout': float(os.getenv('DEFAULT_DB_OPTIONS_TIMEOUT', 5))
}

I saw something like this, but I can't find a way to verify it actually works:

DATABASES[DEFAULT]['OPTIONS'] = {
    'options': '-d statement_timeout=700'
}

I know I can set it directly from the DB like:

set statement_timeout=5000

but I'm looking for a way to do it from Django.

Answer 1

There is no other "Django" way of doing this. The Django way is to use your settings.py like you indicate, except your example is not quite right. It should be:

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql',
        ...
        'OPTIONS': {
            'options': '-c statement_timeout=5000',
            ...
        }
    }
}

The 'OPTIONS' dictionary is for arguments to the database connection string. The list of Postgres arguments can be found here . The options connection string argument allows you to specify command-line arguments for postgres. The -c option is explained here .

Note that the timeout is measured in milliseconds, so the 5000 above means 5 seconds.

Answer 2

I use Django 3.2.16 on Windows 11 then, I set '-c statement_timeout=5000' in OPTIONS and 'SET statement_timeout = 5000;' with cursor.execute() in settings.py as shown below:

# "settings.py"

from django.db import connection

# ...

DATABASES = {
    'default':{
        'ENGINE':'django.db.backends.postgresql',
        'NAME':'postgres',
        'USER':'postgres',
        'PASSWORD':'admin',
        'HOST':'localhost',
        'PORT':'5432',
        # 'ATOMIC_REQUESTS': True,
    },
    'OPTIONS': {
        'options': '-c statement_timeout=5000' # Here
     }
}

cursor = connection.cursor()
cursor.execute('SET statement_timeout = 5000;') # Here

Then, test view with cursor.execute('SELECT pg_sleep(10);') below runs without any errors because statement_timeout = 5000 in settings.py doesn't work in test view :

# "views.py"

from django.db import connection
from django.http import HttpResponse

def test(request):
    cursor = connection.cursor()
    cursor.execute('SELECT pg_sleep(10);')
    
    return HttpResponse("Test")

But, when setting statement_timeout = 5000 in test view as shown below:

# "views.py"

from django.db import connection
from django.http import HttpResponse

def test(request):
    cursor = connection.cursor()
    cursor.execute('SET statement_timeout = 5000;')
    cursor.execute('SELECT pg_sleep(10);')
    
    return HttpResponse("Test")

The error below occurs because statement_timeout = 5000 in test view works properly. * cursor.execute('SET statement_timeout = 5000;') only applies to test view rather than other views so you need to call cursor.execute('SET statement_timeout = 5000;') in each view if you want to apply cursor.execute('SET statement_timeout = 5000;') to each view:

django.db.utils.OperationalError: canceling statement due to statement timeout