diff options
Diffstat (limited to 'django/db/models/sql')
| -rw-r--r-- | django/db/models/sql/compiler.py | 15 | ||||
| -rw-r--r-- | django/db/models/sql/query.py | 5 |
2 files changed, 20 insertions, 0 deletions
diff --git a/django/db/models/sql/compiler.py b/django/db/models/sql/compiler.py index d425c8b32b..ace9cf4c88 100644 --- a/django/db/models/sql/compiler.py +++ b/django/db/models/sql/compiler.py @@ -1,11 +1,13 @@ from django.core.exceptions import FieldError from django.db import connections +from django.db import transaction from django.db.backends.util import truncate_name from django.db.models.sql.constants import * from django.db.models.sql.datastructures import EmptyResultSet from django.db.models.sql.expressions import SQLEvaluator from django.db.models.sql.query import get_proxied_model, get_order_dir, \ select_related_descend, Query +from django.db.utils import DatabaseError class SQLCompiler(object): def __init__(self, query, connection, using): @@ -117,6 +119,14 @@ class SQLCompiler(object): result.append('LIMIT %d' % val) result.append('OFFSET %d' % self.query.low_mark) + if self.query.select_for_update and self.connection.features.has_select_for_update: + # If we've been asked for a NOWAIT query but the backend does not support it, + # raise a DatabaseError otherwise we could get an unexpected deadlock. + nowait = self.query.select_for_update_nowait + if nowait and not self.connection.features.has_select_for_update_nowait: + raise DatabaseError('NOWAIT is not supported on this database backend.') + result.append(self.connection.ops.for_update_sql(nowait=nowait)) + return ' '.join(result), tuple(params) def as_nested_sql(self): @@ -677,6 +687,11 @@ class SQLCompiler(object): resolve_columns = hasattr(self, 'resolve_columns') fields = None has_aggregate_select = bool(self.query.aggregate_select) + # Set transaction dirty if we're using SELECT FOR UPDATE to ensure + # a subsequent commit/rollback is executed, so any database locks + # are released. + if self.query.select_for_update and transaction.is_managed(self.using): + transaction.set_dirty(self.using) for rows in self.execute_sql(MULTI): for row in rows: if resolve_columns: diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py index 59f7bcbf14..f41272cf0f 100644 --- a/django/db/models/sql/query.py +++ b/django/db/models/sql/query.py @@ -125,6 +125,8 @@ class Query(object): self.order_by = [] self.low_mark, self.high_mark = 0, None # Used for offset/limit self.distinct = False + self.select_for_update = False + self.select_for_update_nowait = False self.select_related = False self.related_select_cols = [] @@ -254,6 +256,8 @@ class Query(object): obj.order_by = self.order_by[:] obj.low_mark, obj.high_mark = self.low_mark, self.high_mark obj.distinct = self.distinct + obj.select_for_update = self.select_for_update + obj.select_for_update_nowait = self.select_for_update_nowait obj.select_related = self.select_related obj.related_select_cols = [] obj.aggregates = copy.deepcopy(self.aggregates, memo=memo) @@ -360,6 +364,7 @@ class Query(object): query.clear_ordering(True) query.clear_limits() + query.select_for_update = False query.select_related = False query.related_select_cols = [] query.related_select_fields = [] |