Tablespaces¶
A common paradigm for optimizing performance in database systems is the use of tablespaces to organize disk layout.
Warning
Django does not create the tablespaces for you. Please refer to your database engine’s documentation for details on creating and managing tablespaces.
Declaring tablespaces for tables¶
A tablespace can be specified for the table generated by a model by supplying
the db_tablespace
option inside the model’s
class Meta
. This option also affects tables automatically created for
ManyToManyField
s in the model.
You can use the DEFAULT_TABLESPACE
setting to specify a default value
for db_tablespace
. This is useful for setting
a tablespace for the built-in Django apps and other applications whose code you
cannot control.
Declaring tablespaces for indexes¶
You can pass the db_tablespace
option to a
Field
constructor to specify an alternate tablespace for the Field
’s
column index. If no index would be created for the column, the option is
ignored.
You can use the DEFAULT_INDEX_TABLESPACE
setting to specify
a default value for db_tablespace
.
If db_tablespace
isn’t specified and you didn’t
set DEFAULT_INDEX_TABLESPACE
, the index is created in the same
tablespace as the tables.
An example¶
class TablespaceExample(models.Model):
name = models.CharField(max_length=30, db_index=True, db_tablespace="indexes")
data = models.CharField(max_length=255, db_index=True)
edges = models.ManyToManyField(to="self", db_tablespace="indexes")
class Meta:
db_tablespace = "tables"
In this example, the tables generated by the TablespaceExample
model (i.e.
the model table and the many-to-many table) would be stored in the tables
tablespace. The index for the name field and the indexes on the many-to-many
table would be stored in the indexes
tablespace. The data
field would
also generate an index, but no tablespace for it is specified, so it would be
stored in the model tablespace tables
by default.
Database support¶
PostgreSQL and Oracle support tablespaces. SQLite and MySQL don’t.
When you use a backend that lacks support for tablespaces, Django ignores all tablespace-related options.