Insert election records in bulk.

Otherwise, one can significantly slow nodes down by posting a whole bunch of unique elections.

bigchaindb/backend/localmongodb/query.py

@@ -295,6 +295,13 @@ def store_election(conn, election_id, height, is_concluded):
     )
 
 
+@register_query(LocalMongoDBConnection)
+def store_elections(conn, elections):
+    return conn.run(
+        conn.collection('elections').insert_many(elections)
+    )
+
+
 @register_query(LocalMongoDBConnection)
 def get_validator_set(conn, height=None):
     query = {}

bigchaindb/backend/query.py

@@ -358,6 +358,13 @@ def store_election(conn, election_id, height, is_concluded):
     raise NotImplementedError
 
 
+@singledispatch
+def store_elections(conn, elections):
+    """Store election records in bulk"""
+
+    raise NotImplementedError
+
+
 @singledispatch
 def get_validator_set(conn, height):
     """Get validator set for a given `height`, if `height` is not specified

bigchaindb/elections/election.py

@@ -277,11 +277,15 @@ class Election(Transaction):
            for other concluded elections, if it requires so, the method should
            rely on the database state.
         """
+        # elections placed in this block
+        initiated_elections = []
+        # elections voted for in this block and their votes
         elections = OrderedDict()
         for tx in txns:
             if isinstance(tx, Election):
-                tx.store(bigchain, new_height, is_concluded=False)
-
+                initiated_elections.append({'election_id': tx.id,
+                                            'height': new_height,
+                                            'is_concluded': False})
             if not isinstance(tx, Vote):
                 continue
             election_id = tx.asset['id']
@@ -289,6 +293,9 @@ class Election(Transaction):
                 elections[election_id] = []
             elections[election_id].append(tx)
 
+        if initiated_elections:
+            bigchain.store_elections(initiated_elections)
+
         validator_update = None
         for election_id, votes in elections.items():
             election = bigchain.get_transaction(election_id)

bigchaindb/lib.py

@@ -484,6 +484,9 @@ class BigchainDB(object):
         return backend.query.store_election(self.connection, election_id,
                                             height, is_concluded)
 
+    def store_elections(self, elections):
+        return backend.query.store_elections(self.connection, elections)
+
 
 Block = namedtuple('Block', ('app_hash', 'height', 'transactions'))