Ticket #36502: monkey_patch.py

from django.db.models.sql.compiler import SQLInsertCompiler as BaseSQLInsertCompiler
from django.db.backends.postgresql.compiler import SQLInsertCompiler, InsertUnnest
def monkey_patch_assemble_as_sql(self, fields, value_rows):
    # Specialize bulk-insertion of literal values through UNNEST to
    # reduce the time spent planning the query.
    fields_are_data = [_ for _ in fields if _.get_internal_type() != "ForeignKey"]
    if (
        # The optimization is not worth doing if there is a single
        # row as it will result in the same number of placeholders.
        len(value_rows) <= 1
        # Lack of fields denote the usage of the DEFAULT keyword
        # for the insertion of empty rows.
        or any(field is None for field in fields)
        # Fields that don't use standard internal types might not be
        # unnest'able (e.g. array and geometry types are known to be
        # problematic).
        or any(
            field.get_internal_type() not in self.connection.data_types
            for field in fields_are_data
        )
        # Compilable cannot be combined in an array of literal values.
        or any(any(hasattr(value, "as_sql") for value in row) for row in value_rows)
    ):
        return BaseSQLInsertCompiler.assemble_as_sql(self, fields, value_rows)
    db_types = [field.db_type(self.connection) for field in fields]
    return InsertUnnest(["(%%s)::%s[]" % db_type for db_type in db_types]), [
        list(map(list, zip(*value_rows)))
    ]
SQLInsertCompiler.assemble_as_sql = monkey_patch_assemble_as_sql