225 lines
8.4 KiB
Python
225 lines
8.4 KiB
Python
"""
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PostgreSQL database backend for Django.
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Requires psycopg 2: http://initd.org/projects/psycopg2
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"""
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from django.conf import settings
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from django.db.backends import (BaseDatabaseFeatures, BaseDatabaseWrapper,
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BaseDatabaseValidation)
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from django.db.backends.postgresql_psycopg2.operations import DatabaseOperations
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from django.db.backends.postgresql_psycopg2.client import DatabaseClient
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from django.db.backends.postgresql_psycopg2.creation import DatabaseCreation
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from django.db.backends.postgresql_psycopg2.version import get_version
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from django.db.backends.postgresql_psycopg2.introspection import DatabaseIntrospection
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from django.db.backends.postgresql_psycopg2.schema import DatabaseSchemaEditor
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from django.db.utils import InterfaceError
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from django.utils.encoding import force_str
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from django.utils.functional import cached_property
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from django.utils.safestring import SafeText, SafeBytes
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from django.utils.timezone import utc
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try:
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import psycopg2 as Database
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import psycopg2.extensions
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import psycopg2.extras
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except ImportError as e:
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from django.core.exceptions import ImproperlyConfigured
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raise ImproperlyConfigured("Error loading psycopg2 module: %s" % e)
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DatabaseError = Database.DatabaseError
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IntegrityError = Database.IntegrityError
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psycopg2.extensions.register_type(psycopg2.extensions.UNICODE)
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psycopg2.extensions.register_type(psycopg2.extensions.UNICODEARRAY)
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psycopg2.extensions.register_adapter(SafeBytes, psycopg2.extensions.QuotedString)
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psycopg2.extensions.register_adapter(SafeText, psycopg2.extensions.QuotedString)
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psycopg2.extras.register_uuid()
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def utc_tzinfo_factory(offset):
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if offset != 0:
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raise AssertionError("database connection isn't set to UTC")
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return utc
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class DatabaseFeatures(BaseDatabaseFeatures):
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needs_datetime_string_cast = False
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can_return_id_from_insert = True
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has_real_datatype = True
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can_defer_constraint_checks = True
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has_select_for_update = True
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has_select_for_update_nowait = True
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has_bulk_insert = True
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uses_savepoints = True
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can_release_savepoints = True
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supports_tablespaces = True
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supports_transactions = True
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can_introspect_autofield = True
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can_introspect_ip_address_field = True
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can_introspect_small_integer_field = True
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can_distinct_on_fields = True
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can_rollback_ddl = True
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supports_combined_alters = True
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nulls_order_largest = True
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closed_cursor_error_class = InterfaceError
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has_case_insensitive_like = False
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requires_sqlparse_for_splitting = False
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class DatabaseWrapper(BaseDatabaseWrapper):
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vendor = 'postgresql'
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operators = {
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'exact': '= %s',
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'iexact': '= UPPER(%s)',
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'contains': 'LIKE %s',
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'icontains': 'LIKE UPPER(%s)',
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'regex': '~ %s',
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'iregex': '~* %s',
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'gt': '> %s',
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'gte': '>= %s',
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'lt': '< %s',
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'lte': '<= %s',
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'startswith': 'LIKE %s',
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'endswith': 'LIKE %s',
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'istartswith': 'LIKE UPPER(%s)',
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'iendswith': 'LIKE UPPER(%s)',
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}
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# The patterns below are used to generate SQL pattern lookup clauses when
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# the right-hand side of the lookup isn't a raw string (it might be an expression
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# or the result of a bilateral transformation).
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# In those cases, special characters for LIKE operators (e.g. \, *, _) should be
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# escaped on database side.
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#
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# Note: we use str.format() here for readability as '%' is used as a wildcard for
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# the LIKE operator.
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pattern_esc = r"REPLACE(REPLACE(REPLACE({}, '\', '\\'), '%%', '\%%'), '_', '\_')"
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pattern_ops = {
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'contains': "LIKE '%%' || {} || '%%'",
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'icontains': "LIKE '%%' || UPPER({}) || '%%'",
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'startswith': "LIKE {} || '%%'",
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'istartswith': "LIKE UPPER({}) || '%%'",
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'endswith': "LIKE '%%' || {}",
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'iendswith': "LIKE '%%' || UPPER({})",
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}
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Database = Database
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SchemaEditorClass = DatabaseSchemaEditor
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def __init__(self, *args, **kwargs):
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super(DatabaseWrapper, self).__init__(*args, **kwargs)
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opts = self.settings_dict["OPTIONS"]
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RC = psycopg2.extensions.ISOLATION_LEVEL_READ_COMMITTED
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self.isolation_level = opts.get('isolation_level', RC)
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self.features = DatabaseFeatures(self)
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self.ops = DatabaseOperations(self)
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self.client = DatabaseClient(self)
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self.creation = DatabaseCreation(self)
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self.introspection = DatabaseIntrospection(self)
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self.validation = BaseDatabaseValidation(self)
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def get_connection_params(self):
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settings_dict = self.settings_dict
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# None may be used to connect to the default 'postgres' db
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if settings_dict['NAME'] == '':
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from django.core.exceptions import ImproperlyConfigured
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raise ImproperlyConfigured(
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"settings.DATABASES is improperly configured. "
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"Please supply the NAME value.")
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conn_params = {
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'database': settings_dict['NAME'] or 'postgres',
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}
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conn_params.update(settings_dict['OPTIONS'])
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if 'autocommit' in conn_params:
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del conn_params['autocommit']
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if 'isolation_level' in conn_params:
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del conn_params['isolation_level']
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if settings_dict['USER']:
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conn_params['user'] = settings_dict['USER']
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if settings_dict['PASSWORD']:
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conn_params['password'] = force_str(settings_dict['PASSWORD'])
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if settings_dict['HOST']:
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conn_params['host'] = settings_dict['HOST']
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if settings_dict['PORT']:
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conn_params['port'] = settings_dict['PORT']
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return conn_params
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def get_new_connection(self, conn_params):
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return Database.connect(**conn_params)
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def init_connection_state(self):
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settings_dict = self.settings_dict
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self.connection.set_client_encoding('UTF8')
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tz = 'UTC' if settings.USE_TZ else settings_dict.get('TIME_ZONE')
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if tz:
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try:
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get_parameter_status = self.connection.get_parameter_status
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except AttributeError:
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# psycopg2 < 2.0.12 doesn't have get_parameter_status
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conn_tz = None
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else:
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conn_tz = get_parameter_status('TimeZone')
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if conn_tz != tz:
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cursor = self.connection.cursor()
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try:
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cursor.execute(self.ops.set_time_zone_sql(), [tz])
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finally:
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cursor.close()
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# Commit after setting the time zone (see #17062)
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if not self.get_autocommit():
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self.connection.commit()
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def create_cursor(self):
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cursor = self.connection.cursor()
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cursor.tzinfo_factory = utc_tzinfo_factory if settings.USE_TZ else None
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return cursor
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def _set_isolation_level(self, isolation_level):
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assert isolation_level in range(1, 5) # Use set_autocommit for level = 0
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if self.psycopg2_version >= (2, 4, 2):
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self.connection.set_session(isolation_level=isolation_level)
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else:
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self.connection.set_isolation_level(isolation_level)
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def _set_autocommit(self, autocommit):
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with self.wrap_database_errors:
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if self.psycopg2_version >= (2, 4, 2):
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self.connection.autocommit = autocommit
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else:
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if autocommit:
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level = psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT
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else:
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level = self.isolation_level
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self.connection.set_isolation_level(level)
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def check_constraints(self, table_names=None):
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"""
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To check constraints, we set constraints to immediate. Then, when, we're done we must ensure they
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are returned to deferred.
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"""
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self.cursor().execute('SET CONSTRAINTS ALL IMMEDIATE')
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self.cursor().execute('SET CONSTRAINTS ALL DEFERRED')
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def is_usable(self):
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try:
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# Use a psycopg cursor directly, bypassing Django's utilities.
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self.connection.cursor().execute("SELECT 1")
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except Database.Error:
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return False
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else:
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return True
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@cached_property
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def psycopg2_version(self):
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version = psycopg2.__version__.split(' ', 1)[0]
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return tuple(int(v) for v in version.split('.') if v.isdigit())
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@cached_property
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def pg_version(self):
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with self.temporary_connection():
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return get_version(self.connection)
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