[FIX] core: ormcache is now per regisry.

A cross-registry cache was introduced by e2ea691ce.
The initial idea was praiseworthy but sub-optimal for servers with a
lot of registries.
When there is lot of registry loaded, the cache size was huge and
clearing some entries took a lot of CPU time, increasing the chances
of timeout.

Also, the cache was not cleaned when a registry is removed from
registry LRU (this operation would also consume time).

openerp/models.py

@@ -1814,7 +1814,7 @@ class BaseModel(object):
         ``tools.ormcache`` or ``tools.ormcache_multi``.
         """
         try:
-            self.pool.cache.clear_prefix((self.pool.db_name, self._name))
+            self.pool.cache.clear_prefix((self._name,))
             self.pool._any_cache_cleared = True
         except AttributeError:
             pass

openerp/modules/registry.py

@@ -73,6 +73,7 @@ class Registry(Mapping):
         self.base_registry_signaling_sequence = None
         self.base_cache_signaling_sequence = None
 
+        self.cache = LRU(8192)
         # Flag indicating if at least one model cache has been cleared.
         # Useful only in a multi-process context.
         self._any_cache_cleared = False
@@ -104,10 +105,6 @@ class Registry(Mapping):
         """ Same as ``self[model_name]``. """
         return self.models[model_name]
 
-    @lazy_property
-    def cache(self):
-        return RegistryManager.cache
-
     @lazy_property
     def pure_function_fields(self):
         """ Return the list of pure function fields (field objects) """
@@ -291,7 +288,6 @@ class RegistryManager(object):
 
     """
     _registries = None
-    _cache = None
     _lock = threading.RLock()
     _saved_lock = None
 
@@ -313,18 +309,6 @@ class RegistryManager(object):
             cls._registries = LRU(size)
         return cls._registries
 
-    @classproperty
-    def cache(cls):
-        """ Return the global LRU ormcache. Its keys are tuples with the
-        following structure: (db_name, model_name, method, args...).
-        """
-        with cls.lock():
-            if cls._cache is None:
-                # we allocate 8192 cache entries per registry
-                size = 8192 * cls.registries.count
-                cls._cache = LRU(size)
-            return cls._cache
-
     @classmethod
     def lock(cls):
         """ Return the current registry lock. """

openerp/tools/cache.py

@@ -59,7 +59,7 @@ class ormcache(object):
         return lookup
 
     def lru(self, model):
-        return model.pool.cache, (model.pool.db_name, model._name, self.method)
+        return model.pool.cache, (model._name, self.method)
 
     def lookup(self, method, *args, **kwargs):
         d, key0 = self.lru(args[0])
@@ -181,16 +181,19 @@ def log_ormcache_stats(sig=None, frame=None):
     import threading
 
     me = threading.currentThread()
+    me_dbname = me.dbname
     entries = defaultdict(int)
-    for key in RegistryManager.cache.iterkeys():
-        entries[key[:3]] += 1
+    for reg in RegistryManager.registries.itervalues():
+        for key in reg.cache.iterkeys():
+            entries[key[:3]] += 1
     for key, count in sorted(entries.items()):
         dbname, model_name, method = key
         me.dbname = dbname
         stat = STAT[key]
         _logger.info("%6d entries, %6d hit, %6d miss, %6d err, %4.1f%% ratio, for %s.%s",
-            count, stat.hit, stat.miss, stat.err, stat.ratio, model_name, method.__name__)
+                     count, stat.hit, stat.miss, stat.err, stat.ratio, model_name, method.__name__)
 
+    me.dbname = me_dbname
 
 # For backward compatibility
 cache = ormcache

openerp/tools/lru.py

@@ -123,7 +123,7 @@ class LRU(object):
     def clear_prefix(self, prefix):
         """ Remove from `self` all the items with the given `prefix`. """
         n = len(prefix)
-        for key in self.keys():
+        for key in self.iterkeys():
             if key[:n] == prefix:
                 del self[key]