django-import-export bulk testing

django-import-export-bulk-testing.md

Django Import Export

Bulk import testing

This scripts outlines the steps used to profile bulk loading. The bulk_import.py script is used to profile run duration and memory during bulk load testing.

Pre-requisites

• Docker
• virtualenvwrapper

Test environment

The following tests were run on the following platform:

• Thinkpad T470 i5 processor (Ubuntu 18.04)
• python 3.8.1
• Postgres 10 (docker container)

Install dependencies

# create venv and install django-import-export dependencies
cd <PROJECT_HOME>
mkvirtualenv -p python3 djangoimportexport
pip install -r requirements/base.txt -r requirements/test.txt

Create Postgres DB

export IMPORT_EXPORT_TEST_TYPE=postgres
export IMPORT_EXPORT_POSTGRESQL_USER=pguser
export IMPORT_EXPORT_POSTGRESQL_PASSWORD=pguserpass
export DJANGO_SETTINGS_MODULE=settings

cd <PROJECT_HOME>/tests

# start a local postgres instance
docker-compose -f bulk/docker-compose.yml up -d 

./manage.py migrate
./manage.py test

# only required if you want to login to the Admin site
./manage.py createsuperuser --username admin  --email=email@example.com

Update settings

In order to use the runscript command, add django_extensions to settings.py (INSTALLED_APPS).

Running script

# run creates, updates, and deletes
./manage.py runscript bulk_import

# pass 'create', 'update' or 'delete' to run the single test
./manage.py runscript bulk_import --script-args create

Results

• Used 20k book entries
• Memory is reported as the peak memory value whilst running the test script

bulk_create

Default settings

• default settings
• uses ModelInstanceLoader by default

Condition	Time (secs)	Memory (MB)
use_bulk=False	42.67	16.22
use_bulk=True, batch_size=None	33.72	50.02
use_bulk=True, batch_size=1000	33.21	11.43

Performance tweaks

use_bulk	batch_size	skip_diff	instance_loader	time (secs)	peak mem (MB)
True	1000	True	force_init_instance	9.60	9.4
True	1000	False	CachedInstanceLoader	13.72	9.9
True	1000	True	CachedInstanceLoader	16.12	9.5
True	1000	False	force_init_instance	19.93	10.5
False	n/a	False	force_init_instance	26.59	14.1
True	1000	False	ModelInstanceLoader	28.60	9.7
True	1000	False	ModelInstanceLoader	33.19	10.6
False	n/a	False	ModelInstanceLoader	45.32	16.3

(force_init_instance) means overriding get_or_init_instance() - this can be done when you know for certain that you are importing new rows:

def get_or_init_instance(self, instance_loader, row):
    return self._meta.model(), True

bulk_update

./manage.py runscript bulk_import --script-args update

Default settings

• skip_diff = False
• instance_loader_class = ModelInstanceLoader

Condition	Time (secs)	Memory (MB)
use_bulk=False	82.28	9.33
use_bulk=True, batch_size=None	92.41	202.26
use_bulk=True, batch_size=1000	52.63	11.25

Performance tweaks

• skip_diff = True
• instance_loader_class = CachedInstanceLoader

Condition	Time (secs)	Memory (MB)
use_bulk=False	28.85	20.71
use_bulk=True, batch_size=None	65.11	201.01
use_bulk=True, batch_size=1000	21.56	21.25

• skip_diff = False

Condition	Time (secs)	Memory (MB)
use_bulk=True, batch_size=1000	9.26	8.51
skip_html_diff=True, batch_size=1000	8.69	7.50
skip_unchanged=True, batch_size=1000	5.42	7.34

bulk delete

./manage.py runscript bulk_import --script-args delete

Default settings

• skip_diff = False
• instance_loader_class = ModelInstanceLoader

Condition	Time (secs)	Memory (MB)
use_bulk=False	95.56	31.36
use_bulk=True, batch_size=None	50.20	64.66
use_bulk=True, batch_size=1000	43.77	33.123

Performance tweaks

• skip_diff = True
• instance_loader_class = CachedInstanceLoader

Condition	Time (secs)	Memory (MB)
use_bulk=False	61.66	31.94
use_bulk=True, batch_size=None	14.08	39.40
use_bulk=True, batch_size=1000	15.37	32.70

Checking DB

Note that the db is cleared down after each test run. You need to uncomment the delete() calls to be able to view data.

./manage.py shell_plus

Book.objects.all().count()

Clear down

Optional clear down of resources:

# remove the test db container
docker-compose -f bulk/docker-compose.yml down -v

# remove venv
deactivate
rmvirtualenv djangoimportexport

References

• https://hakibenita.com/fast-load-data-python-postgresql