of threading anything to SA but this is one spot that its its really needed since mappers
are typically "global", and while their state does not change during normal operation, the
initial compilation step does modify internal state significantly, and this step usually
occurs not at module-level initialization time (unless you call compile()) but at first-request
time
- added "compile_mappers()" function as a shortcut to compiling all mappers
-- added "BIGSERIAL" support for postgres table with PGBigInteger/autoincrement
-- fix to MapperExtension create_instance so that entity_name properly associated
+0.3.4
+- general:
+ - global "insure"->"ensure" change. in US english "insure" is actually
+ largely interchangeable with "ensure" (so says the dictionary), so I'm not
+ completely illiterate, but its definitely sub-optimal to "ensure" which is
+ non-ambiguous.
+- sql:
+ - added "BIGSERIAL" support for postgres table with PGBigInteger/autoincrement
+ - fixes to postgres reflection to better handle when schema names are present;
+ thanks to jason (at) ncsmags.com [ticket:402]
+ - fix to correlation of subqueries when the column list of the select statement
+ is constructed with individual calls to append_column(); this fixes an ORM
+ bug whereby nested select statements were not getting correlated with the
+ main select generated by the Query object.
+ - default "timezone" setting is now False. this corresponds to Python's datetime
+ behavior as well as Postgres' timestamp/time types (which is the only timezone-sensitive
+ dialect at the moment) [ticket:414]
+- firebird:
+ - order of constraint creation puts primary key first before all other constraints;
+ required for firebird, not a bad idea for others [ticket:408]
+ - Firebird fix to autoload multifield foreign keys [ticket:409]
+ - Firebird NUMERIC type properly handles a type without precision [ticket:409]
+- orm:
+ - added a mutex to the mapper compilation step. ive been reluctant to add any kind
+ of threading anything to SA but this is one spot that its its really needed since mappers
+ are typically "global", and while their state does not change during normal operation, the
+ initial compilation step does modify internal state significantly, and this step usually
+ occurs not at module-level initialization time (unless you call compile()) but at first-request
+ time
+ - added "compile_mappers()" function as a shortcut to compiling all mappers
+ - fix to MapperExtension create_instance so that entity_name properly associated
with new instance
-- fixes to postgres reflection to better handle when schema names are present;
-thanks to jason (at) ncsmags.com [ticket:402]
-- fix to correlation of subqueries when the column list of the select statement
-is constructed with individual calls to append_column(); this fixes an ORM
-bug whereby nested select statements were not getting correlated with the
-main select generated by the Query object.
-- speed enhancements to ORM object instantiation, eager loading of rows
-- global "insure"->"ensure" change. in US english "insure" is actually
-largely interchangeable with "ensure" (so says the dictionary), so I'm not
-completely illiterate, but its definitely sub-optimal to "ensure" which is
-non-ambiguous.
-- invalid options sent to 'cascade' string will raise an exception [ticket:406]
-- fixed bug in mapper refresh/expire whereby eager loaders didnt properly re-populate
-item lists [ticket:407]
-- order of constraint creation puts primary key first before all other constraints;
-required for firebird, not a bad idea for others [ticket:408]
-- Firebird fix to autoload multifield foreign keys [ticket:409]
-- Firebird NUMERIC type properly handles a type without precision [ticket:409]
-- fix to post_update to insure rows are updated even for non insert/delete scenarios
-[ticket:413]
-- default "timezone" setting is now False. this corresponds to Python's datetime
-behavior as well as Postgres' timestamp/time types (which is the only timezone-sensitive
-dialect at the moment) [ticket:414]
-- added an error message if you actually try to modify primary key values on an entity
-and then flush it.
+ - speed enhancements to ORM object instantiation, eager loading of rows
+ - invalid options sent to 'cascade' string will raise an exception [ticket:406]
+ - fixed bug in mapper refresh/expire whereby eager loaders didnt properly re-populate
+ item lists [ticket:407]
+ - fix to post_update to insure rows are updated even for non insert/delete scenarios
+ [ticket:413]
+ - added an error message if you actually try to modify primary key values on an entity
+ and then flush it.
0.3.3
- string-based FROM clauses fixed, i.e. select(..., from_obj=["sometext"])
from sqlalchemy.orm.session import object_session
__all__ = ['relation', 'backref', 'eagerload', 'lazyload', 'noload', 'deferred', 'defer', 'undefer', 'extension',
- 'mapper', 'clear_mappers', 'clear_mapper', 'class_mapper', 'object_mapper', 'MapperExtension', 'Query',
+ 'mapper', 'clear_mappers', 'compile_mappers', 'clear_mapper', 'class_mapper', 'object_mapper', 'MapperExtension', 'Query',
'cascade_mappers', 'polymorphic_union', 'create_session', 'synonym', 'contains_eager', 'EXT_PASS', 'object_session'
]
Used with the 'properties' dictionary sent to mapper()."""
return properties.SynonymProperty(name, proxy=proxy)
-
+
+def compile_mappers():
+ """compile all mappers that have been defined.
+
+ this is equivalent to calling compile() on any individual mapper."""
+ if not len(mapper_registry):
+ return
+ mapper_registry.values()[0].compile()
+
def clear_mappers():
"""remove all mappers that have been created thus far.
# returned by a MapperExtension method to indicate a "do nothing" response
EXT_PASS = object()
+
+# lock used to synchronize the "mapper compile" step
+_COMPILE_MUTEX = util.threading.Lock()
class Mapper(object):
"""Defines the correlation of class attributes to database table columns.
this is the 'external' version of the method which is not reentrant."""
if self.__is_compiled:
return self
+ _COMPILE_MUTEX.acquire()
+ try:
+ # double-check inside mutex
+ if self.__is_compiled:
+ return self
+ self._compile_all()
- self._compile_all()
-
- # if we're not primary, compile us
- if self.non_primary:
- self._do_compile()
- self._initialize_properties()
+ # if we're not primary, compile us
+ if self.non_primary:
+ self._do_compile()
+ self._initialize_properties()
- return self
-
+ return self
+ finally:
+ _COMPILE_MUTEX.release()
+
def _compile_all(self):
# compile all primary mappers
for mapper in mapper_registry.values():
--- /dev/null
+# tests the COMPILE_MUTEX in mapper compilation
+
+from sqlalchemy import *
+import thread, time, random
+from sqlalchemy.orm import mapperlib
+
+meta = BoundMetaData('sqlite:///foo.db')
+
+t1 = Table('t1', meta,
+ Column('c1', Integer, primary_key=True),
+ Column('c2', String(30))
+ )
+
+t2 = Table('t2', meta,
+ Column('c1', Integer, primary_key=True),
+ Column('c2', String(30)),
+ Column('t1c1', None, ForeignKey('t1.c1'))
+)
+meta.create_all()
+
+class T1(object):
+ pass
+
+class T2(object):
+ pass
+
+class FakeLock(object):
+ def acquire(self):pass
+ def release(self):pass
+
+# uncomment this to disable the mutex in mapper compilation;
+# should produce thread collisions
+#mapperlib._COMPILE_MUTEX = FakeLock()
+
+existing_compile_all = mapperlib.Mapper._compile_all
+state = [False]
+# decorate mapper's _compile_all() method; the mutex in mapper.compile()
+# should insure that this method is only called once by a single thread only
+def monkeypatch_compile_all(self):
+ if state[0]:
+ raise "thread collision"
+ state[0] = True
+ try:
+ print "compile", thread.get_ident()
+ time.sleep(1 + random.random())
+ existing_compile_all(self)
+ finally:
+ state[0] = False
+mapperlib.Mapper._compile_all = monkeypatch_compile_all
+
+def run1():
+ print "T1", thread.get_ident()
+ class_mapper(T1)
+
+def run2():
+ print "T2", thread.get_ident()
+ class_mapper(T2)
+
+for i in range(0,1):
+ clear_mappers()
+ mapper(T1, t1, properties={'t2':relation(T2, backref="t1")})
+ mapper(T2, t2)
+ #compile_mappers()
+ print "START"
+ for j in range(0, 5):
+ thread.start_new_thread(run1, ())
+ thread.start_new_thread(run2, ())
+ print "WAIT"
+ time.sleep(5)
+
projects / thirdparty / sqlalchemy / sqlalchemy.git / commitdiff
