https://github.com/cockroachdb/django-cockroachdb
CockroachDB Backend for Django
https://github.com/cockroachdb/django-cockroachdb
Last synced: 9 days ago
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CockroachDB Backend for Django
- Host: GitHub
- URL: https://github.com/cockroachdb/django-cockroachdb
- Owner: cockroachdb
- License: apache-2.0
- Created: 2019-06-11T22:57:38.000Z (about 6 years ago)
- Default Branch: master
- Last Pushed: 2025-05-22T20:07:02.000Z (about 1 month ago)
- Last Synced: 2025-06-13T14:02:32.098Z (13 days ago)
- Language: Python
- Homepage: http://cockroachlabs.com
- Size: 322 KB
- Stars: 168
- Watchers: 50
- Forks: 28
- Open Issues: 14
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
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README
# CockroachDB backend for Django
## Prerequisites
You must install:
* [psycopg](https://pypi.org/project/psycopg/), which may have some
prerequisites [depending on which version you use](https://www.psycopg.org/psycopg3/docs/basic/install.html).
You can also use either:
* [psycopg2](https://pypi.org/project/psycopg2/), which has some
[prerequisites](https://www.psycopg.org/docs/install.html#prerequisites) of
its own.
* [psycopg2-binary](https://pypi.org/project/psycopg2-binary/)
The binary package is a practical choice for development and testing but in
production it is advised to use the package built from sources.
## Install and usage
Use the version of django-cockroachdb that corresponds to your version of
Django. For example, to get the latest compatible release for Django 5.2.x:
`pip install django-cockroachdb==5.2.*`
The minor release number of Django doesn't correspond to the minor release
number of django-cockroachdb. Use the latest minor release of each.
Configure the Django `DATABASES` setting similar to this:
```python
DATABASES = {
'default': {
'ENGINE': 'django_cockroachdb',
'NAME': 'django',
'USER': 'myprojectuser',
'PASSWORD': '',
'HOST': 'localhost',
'PORT': '26257',
# If connecting with SSL, include the section below, replacing the
# file paths as appropriate.
'OPTIONS': {
'sslmode': 'verify-full',
'sslrootcert': '/certs/ca.crt',
# Either sslcert and sslkey (below) or PASSWORD (above) is
# required.
'sslcert': '/certs/client.myprojectuser.crt',
'sslkey': '/certs/client.myprojectuser.key',
# If applicable
'options': '--cluster={routing-id}',
},
},
}
```
If using Kerberos authentication, you can specify a custom service name in
`'OPTIONS'` using the key `'krbsrvname'`.
## Notes on Django fields
- `IntegerField` uses the same storage as `BigIntegerField` so `IntegerField`
is introspected by `inspectdb` as `BigIntegerField`.
- `AutoField` and `BigAutoField` are both stored as
[integer](https://www.cockroachlabs.com/docs/stable/int.html) (64-bit) with
[`DEFAULT unique_rowid()`](https://www.cockroachlabs.com/docs/stable/functions-and-operators.html#id-generation-functions).
## Notes on Django QuerySets
- [`QuerySet.explain()`](https://docs.djangoproject.com/en/stable/ref/models/querysets/#explain)
accepts `verbose`, `types`, `opt`, `vec`, and `distsql` options which
correspond to [CockroachDB's parameters](https://www.cockroachlabs.com/docs/stable/explain.html#parameters).
For example:
```python
>>> Choice.objects.explain(opt=True, verbose=True)
'scan polls_choice\n ├── columns: id:1 question_id:4 choice_text:2 votes:3\n ├── stats: [rows=1]\n ├── cost: 1.1\n ├── key: (1)\n ├── fd: (1)-->(2-4)\n └── prune: (1-4)'
```
## FAQ
## GIS support
To use `django.contrib.gis` with CockroachDB, use
`'ENGINE': 'django_cockroachdb_gis'` in Django's `DATABASES` setting.
## Disabling CockroachDB telemetry
By default, CockroachDB sends the version of django-cockroachdb that you're
using back to Cockroach Labs. To disable this, set
`DISABLE_COCKROACHDB_TELEMETRY = True` in your Django settings.
## Known issues and limitations in CockroachDB 25.1.x and earlier
- CockroachDB [can't disable constraint checking](https://github.com/cockroachdb/cockroach/issues/19444),
which means certain things in Django like forward references in fixtures
aren't supported.
- Migrations have some limitations. CockroachDB doesn't support:
- [changing column type if it's part of an index](https://go.crdb.dev/issue/47636)
- dropping or changing a table's primary key
- The `Field.db_comment` and `Meta.db_table_comment` options aren't supported
due to [poor performance](https://github.com/cockroachdb/cockroach/issues/95068).
- Unsupported queries:
- [Mixed type addition in SELECT](https://github.com/cockroachdb/django-cockroachdb/issues/19):
`unsupported binary operator: + `
- [Division that yields a different type](https://github.com/cockroachdb/django-cockroachdb/issues/21):
`unsupported binary operator: / (desired )`
- [The power() database function doesn't accept negative exponents](https://github.com/cockroachdb/django-cockroachdb/issues/22):
`power(): integer out of range`
- [sum() doesn't support arguments of different types](https://github.com/cockroachdb/django-cockroachdb/issues/73):
`sum(): unsupported binary operator: + `
- [greatest() doesn't support arguments of different types](https://github.com/cockroachdb/django-cockroachdb/issues/74):
`greatest(): expected to be of type , found type `
- [`SmallAutoField` generates values that are too large for any corresponding foreign keys](https://github.com/cockroachdb/django-cockroachdb/issues/84).
- GIS:
- Some database functions aren't supported: `AsGML`, `AsKML`, `AsSVG`,
and `GeometryDistance`.
- Some 3D functions or signatures aren't supported: `ST_3DPerimeter`,
`ST_3DExtent`, `ST_Scale`, and `ST_LengthSpheroid`.
- The `Length` database function isn't supported on geodetic fields:
[st_lengthspheroid(): unimplemented](https://github.com/cockroachdb/cockroach/issues/48968).
- `Union` may crash with
[unknown signature: st_union(geometry, geometry)](https://github.com/cockroachdb/cockroach/issues/49064).
- The spheroid argument of ST_DistanceSpheroid
[isn't supported](https://github.com/cockroachdb/cockroach/issues/48922):
`unknown signature: st_distancespheroid(geometry, geometry, string)`.
- These lookups aren't supported:
- [contained (@)](https://github.com/cockroachdb/cockroach/issues/56124)
- [exact/same_as (~=)](https://github.com/cockroachdb/cockroach/issues/57096)
- [left (<<) and right (>>)](https://github.com/cockroachdb/cockroach/issues/57092)
- [overlaps_left (&<), overlaps_right (&>), overlaps_above (&<|),
overlaps_below (&>|)](https://github.com/cockroachdb/cockroach/issues/57098)
- [strictly_above (|>>), strictly_below (<<|)](https://github.com/cockroachdb/cockroach/issues/57095)
## Known issues and limitations in CockroachDB 24.3.x and earlier
- CockroachDB executes `ALTER COLUMN` queries asynchronously which is at
odds with Django's assumption that the database is altered before the next
migration operation begins. CockroachDB will give an error like
`unimplemented: table <...> is currently undergoing a schema change` if a
later operation tries to modify the table before the asynchronous query
finishes.