diff --git a/chainsyncer/backend/memory.py b/chainsyncer/backend/memory.py
index 14f7fdf..2e75496 100644
--- a/chainsyncer/backend/memory.py
+++ b/chainsyncer/backend/memory.py
@@ -14,6 +14,8 @@ class MemBackend:
         self.flags = 0
         self.target_block = target_block
         self.db_session = None
+        self.filter_names = []
+        self.filter_values = []
 
 
     def connect(self):
@@ -28,6 +30,8 @@ class MemBackend:
         logg.debug('stateless backend received {} {}'.format(block_height, tx_height))
         self.block_height = block_height
         self.tx_height = tx_height
+        for i in range(len(self.filter_values)):
+            self.filter_values[i] = False
 
 
     def get(self):
@@ -39,11 +43,13 @@ class MemBackend:
 
 
     def register_filter(self, name):
-        pass
+        self.filter_names.append(name)
+        self.filter_values.append(False)
 
 
     def complete_filter(self, n):
-        pass
+        self.filter_values[n-1] = True
+        logg.debug('set filter {}'.format(self.filter_names[n-1]))
 
 
     def __str__(self):
diff --git a/chainsyncer/driver.py b/chainsyncer/driver.py
index 661c0f2..440e9ae 100644
--- a/chainsyncer/driver.py
+++ b/chainsyncer/driver.py
@@ -72,6 +72,11 @@ class Syncer:
         self.backend.register_filter(str(f))
 
 
+    def process_single(self, conn, block, tx, block_height, tx_index):
+        self.backend.set(block_height, tx_index)
+        self.filter.apply(conn, block, tx)
+
+
 class BlockPollSyncer(Syncer):
 
     def __init__(self, backend, pre_callback=None, block_callback=None, post_callback=None):
@@ -120,14 +125,16 @@ class HeadSyncer(BlockPollSyncer):
         while True:
             try:
                 tx = block.tx(i)
-                rcpt = conn.do(receipt(tx.hash))
-                tx.apply_receipt(rcpt)
-                self.backend.set(block.number, i)
-                self.filter.apply(conn, block, tx)
             except IndexError as e:
                 logg.debug('index error syncer rcpt get {}'.format(e))
                 self.backend.set(block.number + 1, 0)
                 break
+
+            rcpt = conn.do(receipt(tx.hash))
+            tx.apply_receipt(rcpt)
+    
+            self.process_single(conn, block, tx, block.number, i)
+                        
             i += 1
         
 
diff --git a/sql_requirements.txt b/sql_requirements.txt
new file mode 100644
index 0000000..602c2c5
--- /dev/null
+++ b/sql_requirements.txt
@@ -0,0 +1,2 @@
+psycopg2==2.8.6
+SQLAlchemy==1.3.20
diff --git a/tests/test_interrupt.py b/tests/test_interrupt.py
new file mode 100644
index 0000000..4cd61c4
--- /dev/null
+++ b/tests/test_interrupt.py
@@ -0,0 +1,106 @@
+# standard imports
+import logging
+import unittest
+import os
+
+# external imports
+from chainlib.chain import ChainSpec
+from hexathon import add_0x
+
+# local imports
+from chainsyncer.backend.memory import MemBackend
+from chainsyncer.driver import HeadSyncer
+from chainsyncer.error import NoBlockForYou
+
+# test imports
+from tests.base import TestBase
+
+logging.basicConfig(level=logging.DEBUG)
+logg = logging.getLogger()
+
+
+class TestSyncer(HeadSyncer):
+
+
+    def __init__(self, backend, tx_counts=[]):
+        self.tx_counts = tx_counts
+        super(TestSyncer, self).__init__(backend)
+
+
+    def get(self, conn):
+        if self.backend.block_height == self.backend.target_block:
+            raise NoBlockForYou()
+        if self.backend.block_height > len(self.tx_counts):
+            return []
+
+        block_txs = []
+        for i in range(self.tx_counts[self.backend.block_height]):
+            block_txs.append(add_0x(os.urandom(32).hex()))
+      
+        return block_txs
+
+
+    def process(self, conn, block):
+        i = 0
+        for tx in block:
+            self.process_single(conn, block, tx, self.backend.block_height, i)
+            i += 1
+
+
+
+class NaughtyCountExceptionFilter:
+
+    def __init__(self, name, croak_on):
+        self.c = 0
+        self.croak = croak_on
+        self.name = name
+
+
+    def filter(self, conn, block, tx, db_session=None):
+        self.c += 1
+        if self.c == self.croak:
+            raise RuntimeError('foo')
+
+
+    def __str__(self):
+        return '{} {}'.format(self.__class__.__name__, self.name)
+
+
+class CountFilter:
+
+    def __init__(self, name):
+        self.c = 0
+        self.name = name
+
+
+    def filter(self, conn, block, tx, db_session=None):
+        self.c += 1
+
+
+    def __str__(self):
+        return '{} {}'.format(self.__class__.__name__, self.name)
+
+
+class TestInterrupt(unittest.TestCase):
+
+    def setUp(self):
+        self.chain_spec = ChainSpec('foo', 'bar', 42, 'baz')
+        self.backend = MemBackend(self.chain_spec, None, target_block=2)
+        self.syncer = TestSyncer(self.backend, [4, 2, 3])
+
+    def test_filter_interrupt(self):
+       
+        fltrs = [
+            CountFilter('foo'),
+            CountFilter('bar'),
+            NaughtyCountExceptionFilter('xyzzy', 2),
+            CountFilter('baz'),
+                ]
+
+        for fltr in fltrs:
+            self.syncer.add_filter(fltr)
+
+        self.syncer.loop(0.1, None)
+
+if __name__ == '__main__':
+    unittest.main()