#27996: Add pgcrypto extension and GEN_RANDOM_UUID function to contrib.postgres
-------------------------------------+-------------------------------------
Reporter: Paolo Melchiorre | Owner: Paolo
| Melchiorre
Type: New feature | Status: assigned
Component: contrib.postgres | Version: master
Severity: Normal | Resolution:
Keywords: uuid extension | Triage Stage: Accepted
function random postgresql |
cryptography |
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Description changed by Paolo Melchiorre:
Old description:
> After the introduction of the UUID Field in Django 1.8, I believe that
> django.contrib.postgres could benefit from some custom functions based on
> the pgcrypto extension of PostgreSQL (see
> https://www.postgresql.org/docs/9.6/static/pgcrypto.html). That kind of
> functions would be very helpful for apply a migration that adds a unique
> non-nullable field to a table with existing rows.
>
> Starting from "Migrations that add unique fields" (see
> https://docs.djangoproject.com/en/dev/howto/writing-migrations
> /#migrations-that-add-unique-fields) I speed up the `gen_uuid` using
> `GEN_RANDOM_UUID` function, I change the function from:
>
> {{{
> import uuid
>
> def gen_uuid(apps, schema_editor):
> MyModel = apps.get_model('myapp', 'MyModel')
> for row in MyModel.objects.all():
> row.uuid = uuid.uuid4()
> row.save(update_fields=['uuid'])
> }}}
>
> to
>
> {{{
> from django.contrib.postgres.functions import RandomUUID
>
> def gen_uuid(apps, schema_editor):
> MyModel = apps.get_model('myapp', 'MyModel')
> MyModel.objects.update(uuid=RandomUUID())
> }}}
>
> Using this function on my system the time to migrate more than 10000
> objects decreased from
>
> {{{
> real 0m15.988s
> user 0m10.680s
> sys 0m0.508s
> }}}
>
> to
>
> {{{
> real 0m2.957s
> user 0m1.736s
> sys 0m0.072s
> }}}
>
> I already implemented a solution for thi feature and I'm crating a
> related pull request.
New description:
After the introduction of the UUID Field in Django 1.8, I believe that
django.contrib.postgres could benefit from some custom functions based on
the pgcrypto extension of PostgreSQL (see
https://www.postgresql.org/docs/9.6/static/pgcrypto.html). That kind of
functions would be very helpful for apply a migration that adds a unique
non-nullable field to a table with existing rows.
Starting from "Migrations that add unique fields" (see
https://docs.djangoproject.com/en/dev/howto/writing-migrations
/#migrations-that-add-unique-fields) I speed up the `gen_uuid` using
`GEN_RANDOM_UUID` function changing it from:
{{{
import uuid
def gen_uuid(apps, schema_editor):
MyModel = apps.get_model('myapp', 'MyModel')
for row in MyModel.objects.all():
row.uuid = uuid.uuid4()
row.save(update_fields=['uuid'])
}}}
to
{{{
from django.contrib.postgres.functions import RandomUUID
def gen_uuid(apps, schema_editor):
MyModel = apps.get_model('myapp', 'MyModel')
MyModel.objects.update(uuid=RandomUUID())
}}}
Using this function on my system the time to migrate more than 10000
objects decreased from
{{{
real 0m15.988s
user 0m10.680s
sys 0m0.508s
}}}
to
{{{
real 0m2.957s
user 0m1.736s
sys 0m0.072s
}}}
I already implemented a solution for thi feature and I'm crating a related
pull request.
--
--
Ticket URL: <https://code.djangoproject.com/ticket/27996#comment:3>
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