Increase max bulk_batch_size

[danifus]

The previous limit was a max of 1000 query parameters. This is changed
to a max of 1000 rows (the max number of rows allowed for inserting in a
single statement by mssql) or however many rows can be inserted while
keeping the number of query parameters below 2050 per insert statement
(mssql reports a max allowed of 2100 parameters but a few parameters are
reserved for executing the query).

[absci]

Hi, thanks for your contribution, there's one unit test that failed. Is it possible for you to fix it?

ERROR: test_empty_model (bulk_create.tests.BulkCreateTests)

Traceback (most recent call last):
File "/home/vsts/work/1/s/django/tests/bulk_create/tests.py", line 205, in test_empty_model
NoFields.objects.bulk_create([NoFields() for i in range(2)])
File "/home/vsts/work/1/s/.tox/py37-django30/lib/python3.7/site-packages/django/db/models/manager.py", line 82, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/home/vsts/work/1/s/.tox/py37-django30/lib/python3.7/site-packages/django/db/models/query.py", line 493, in bulk_create
objs_without_pk, fields, batch_size, ignore_conflicts=ignore_conflicts,
File "/home/vsts/work/1/s/.tox/py37-django30/lib/python3.7/site-packages/django/db/models/query.py", line 1215, in _batched_insert
batch_size = (batch_size or max(ops.bulk_batch_size(fields, objs), 1))
File "/home/vsts/work/1/s/.tox/py37-django30/lib/python3.7/site-packages/mssql/operations.py", line 59, in bulk_batch_size
return min(1000, max_query_params // fields_len)
ZeroDivisionError: integer division or modulo by zero

[ghost]

All CLA requirements met.

[danifus]

Hi, I got distracted before the CI finished :p

I've pushed a fix which should address that issue.

[absci]

Thanks for this contribution, it has been merged.