Use one lock per database for issue627

CHANGELOG

@@ -1,3 +1,4 @@
+* Use one lock per database
 * Improve netrpc communication speed
 * Add contextual domain on inherited views
 * Allow to use globals in domain and states

trytond/pooler.py

@@ -5,6 +5,7 @@ import logging
 from threading import RLock
 
 _LOCK = RLock()
+_LOCKS = {}
 _DB = {}
 _POOL = {}
 _POOL_WIZARD = {}
@@ -15,6 +16,9 @@ def get_db_and_pool(db_name, update_module=False, wizard=False, report=False,
 
     restart = False
     _LOCK.acquire()
+    lock = _LOCKS.setdefault(db_name, RLock())
+    _LOCK.release()
+    lock.acquire()
     try:
         if db_name in _DB:
             database = _DB[db_name]
@@ -51,7 +55,7 @@ def get_db_and_pool(db_name, update_module=False, wizard=False, report=False,
             restart = not load_modules(database, pool, pool_wizard, pool_report,
                     update_module, lang)
     finally:
-        _LOCK.release()
+        lock.release()
     if restart:
         restart_pool(db_name)
 
@@ -63,16 +67,22 @@ def get_db_and_pool(db_name, update_module=False, wizard=False, report=False,
 
 def restart_pool(db_name, update_module=False, lang=None):
     _LOCK.acquire()
+    lock = _LOCKS.setdefault(db_name, RLock())
+    _LOCK.release()
+    lock.acquire()
     try:
         del _POOL[db_name]
         del _POOL_WIZARD[db_name]
         del _POOL_REPORT[db_name]
     finally:
-        _LOCK.release()
+        lock.release()
     return get_db_and_pool(db_name, update_module=update_module, lang=lang)
 
 def close_db(db_name):
     _LOCK.acquire()
+    lock = _LOCKS.setdefault(db_name, RLock())
+    _LOCK.release()
+    lock.acquire()
     try:
         if db_name in _DB:
             _DB[db_name].close()
@@ -80,10 +90,14 @@ def close_db(db_name):
         if db_name in _POOL:
             del _POOL[db_name]
     finally:
-        _LOCK.release()
+        lock.release()
 
-def get_db_only(db_name, verbose=True):
+def get_db_only(db_name, verbose=True, blocking=True):
     _LOCK.acquire()
+    lock = _LOCKS.setdefault(db_name, RLock())
+    _LOCK.release()
+    if not lock.acquire(blocking):
+        return None
     try:
         if db_name in _DB:
             database = _DB[db_name]
@@ -94,7 +108,7 @@ def get_db_only(db_name, verbose=True):
             database = db_connect(db_name)
             _DB[db_name] = database
     finally:
-        _LOCK.release()
+        lock.release()
     return database
 
 def get_db(db_name):

trytond/web_service/db.py

@@ -232,7 +232,11 @@ class DB(Service):
                         "ORDER BY datname")
             res = []
             for db_name, in cursor.fetchall():
-                cursor2 = pooler.get_db_only(db_name, verbose=False).cursor()
+                database = pooler.get_db_only(db_name, verbose=False,
+                        blocking=False)
+                if not database:
+                    continue
+                cursor2 = database.cursor()
                 if not cursor2.test():
                     cursor2.close()
                     pooler.close_db(db_name)