Add support for model tables on different Postgres schemas

[brmejia]

Problem

Unable to use the command pgpartition if the model table is using a schema other than public

The model definition is something like this

class MonthTimeseriesLong(PostgresPartitionedModel):
    """
    ... fields
    """
    class PartitioningMeta:
        method = PostgresPartitioningMethod.RANGE
        key = ["timestamp"]

    class Meta:
        ...
        db_table = 'timeseries"."tpa_ts_timeseries_long_month'
        ...

Migrations are working good and the tables are created in the right schema whern migrate is executed. However, pgpartition command fails after proposed partitions are accepted:

No table is found because the query made inside the method get_partitioned_tables of PostgresIntrospection returns only the table name and the following strings are being compared: 'timeseries"."tpa_ts_timeseries_long_month' == 'tpa_ts_timeseries_long_month'

Solution

Split by "." the table name defined on the model and trim remaining quotes in order to perform the comparison.

Test results

tox

benchmarks

[Photonios]

Django doesn't have proper support for database schemas, see: https://code.djangoproject.com/ticket/6148

I am happy to merge limited support for this, but this implementation leaves a lot to be desired:

• Breaks on table names that need escaping/quoting.
• Breaks when the table name or schema name is properly quoted ('"schema"."table").
• Breaks when two tables in different schemas have the same name.
• No tests to prevent this from breaking in the future.

You'd have to use something like PostgreSQL parse_ident to do this properly. There are also other introspection methods that don't support this properly. I don't think just this patch is sufficient to fully make this work.