- fixes to ShardedSession to work with deferred columns [ticket:771].

- user-defined shard_chooser() function must accept "clause=None"
  argument; this is the ClauseElement passed to session.execute(statement)
  and can be used to determine correct shard id (since execute() doesn't
  take an instance)

1 files changed, 2 insertions, 1 deletions

diff --git a/examples/sharding/attribute_shard.py b/examples/sharding/attribute_shard.py
index 25da98872..0a9e992a3 100644
--- a/examples/sharding/attribute_shard.py
+++ b/examples/sharding/attribute_shard.py
@@ -22,6 +22,7 @@ from sqlalchemy import *
 from sqlalchemy.orm import *
 from sqlalchemy.orm.shard import ShardedSession
 from sqlalchemy.sql import operators
+from sqlalchemy import sql
 import datetime
 
 # step 2. databases
@@ -107,7 +108,7 @@ shard_lookup = {
 # note that we need to define conditions for 
 # the WeatherLocation class, as well as our secondary Report class which will
 # point back to its WeatherLocation via its 'location' attribute.
-def shard_chooser(mapper, instance):
+def shard_chooser(mapper, instance, clause=None):
     if isinstance(instance, WeatherLocation):
         return shard_lookup[instance.continent]
     else: