Implement dropPartition() on database manager to remove objects and transactions

not related to partitions currently assigned to a storage node. This is required
because an old node can come back, get a new UUID, start replication and a
conflict on (oid, serial) with the cluster it is joining. As there is now check
on the object integrity, the object will not be replicated and a bad object will
be kept. So during storage initialization, after getting the full partition
table, a storage look if there is partitions unassigned to it and drop data for
those partitions.


git-svn-id: https://svn.erp5.org/repos/neo/branches/prototype3@1228 71dcc9de-d417-0410-9af5-da40c76e7ee4

neo/storage/database.py

@@ -127,6 +127,12 @@ class DatabaseManager(object):
         thrown away."""
         raise NotImplementedError('this method must be overridden')
 
+    def dropPartition(self, offset):
+        """ Drop objects and transactions assigned to a partition table,
+        this should be called only during storage initialization, to clear
+        existing data that could be stored by a previous cluster life """
+        raise NotImplementedError('this method must be overriden')
+
     def dropUnfinishedData(self):
         """Drop any unfinished data from a database."""
         raise NotImplementedError('this method must be overridden')

neo/storage/handlers/initialization.py

@@ -48,8 +48,16 @@ class InitializationHandler(BaseMasterHandler):
         # Install the partition table into the database for persistency.
         cell_list = []
         for offset in xrange(app.pt.getPartitions()):
+            assigned_to_me = False
             for cell in pt.getCellList(offset):
                 cell_list.append((offset, cell.getUUID(), cell.getState()))
+                if cell.getUUID() == app.uuid:
+                    assigned_to_me = True
+            if not assigned_to_me:
+                logging.warning('drop data for partition %d' % offset)
+                # not for me, delete objects database
+                app.dm.dropPartition(app.pt.getPartitions(), offset)
+
         app.dm.setPartitionTable(ptid, cell_list)
         self.app.has_partition_table = True
 

neo/storage/mysqldb.py

@@ -369,6 +369,18 @@ class MySQLDatabaseManager(DatabaseManager):
     def setPartitionTable(self, ptid, cell_list):
         self.doSetPartitionTable(ptid, cell_list, True)
 
+    def dropPartition(self, num_partitions, offset):
+        q = self.query
+        self.begin()
+        try:
+            q("""DELETE FROM obj WHERE MOD(oid, %d) = %d""" % 
+                (num_partitions, offset))
+            q("""DELETE FROM trans WHERE MOD(oid, %d) = %d""" % 
+                (num_partitions, offset))
+        except:
+            self.rollback()
+        self.commit()
+
     def dropUnfinishedData(self):
         q = self.query
         self.begin()