I have to insert 8000+ records into a SQLite database using Django's ORM. This operation needs to be run as a cronjob about once per minute.
At the moment I'm using a for loop to iterate through all the items and then insert them one by one.
Example:
for item in items:
entry = Entry(a1=item.a1, a2=item.a2)
entry.save()
What is an efficient way of doing this?
Edit: A little comparison between the two insertion methods.
Without commit_manually decorator (11245 records):
nox@noxdevel marinetraffic]$ time python manage.py insrec
real 1m50.288s
user 0m6.710s
sys 0m23.445s
Using commit_manually decorator (11245 records):
[nox@noxdevel marinetraffic]$ time python manage.py insrec
real 0m18.464s
user 0m5.433s
sys 0m10.163s
Note: The test script also does some other operations besides inserting into the database (downloads a ZIP file, extracts an XML file from the ZIP archive, parses the XML file) so the time needed for execution does not necessarily represent the time needed to insert the records.
You want to check out django.db.transaction.commit_manually
.
http://docs.djangoproject.com/en/dev/topics/db/transactions/#django-db-transaction-commit-manually
So it would be something like:
from django.db import transaction
@transaction.commit_manually
def viewfunc(request):
...
for item in items:
entry = Entry(a1=item.a1, a2=item.a2)
entry.save()
transaction.commit()
Which will only commit once, instead at each save().
In django 1.3 context managers were introduced. So now you can use transaction.commit_on_success() in a similar way:
from django.db import transaction
def viewfunc(request):
...
with transaction.commit_on_success():
for item in items:
entry = Entry(a1=item.a1, a2=item.a2)
entry.save()
In django 1.4, bulk_create
was added, allowing you to create lists of your model objects and then commit them all at once.
NOTE the save method will not be called when using bulk create.
>>> Entry.objects.bulk_create([
... Entry(headline="Django 1.0 Released"),
... Entry(headline="Django 1.1 Announced"),
... Entry(headline="Breaking: Django is awesome")
... ])
In django 1.6, transaction.atomic was introduced, intended to replace now legacy functions commit_on_success
and commit_manually
.
from the django documentation on atomic:
atomic is usable both as a decorator:
from django.db import transaction
@transaction.atomic
def viewfunc(request):
# This code executes inside a transaction.
do_stuff()
and as a context manager:
from django.db import transaction
def viewfunc(request):
# This code executes in autocommit mode (Django's default).
do_stuff()
with transaction.atomic():
# This code executes inside a transaction.
do_more_stuff()