diff --git a/minode/connection.py b/minode/connection.py
index 0d44a24..881f90b 100644
--- a/minode/connection.py
+++ b/minode/connection.py
@@ -285,22 +285,11 @@ class ConnectionBase(threading.Thread):
         if len(addr) != 0:
             self.send_queue.put(message.Addr(addr))
 
-        with shared.objects_lock:
-            if len(shared.objects) > 0:
-                to_send = {
-                    vector for vector in shared.objects.keys()
-                    if shared.objects[vector].expires_time > time.time()}
-                while len(to_send) > 0:
-                    if len(to_send) > 10000:
-                        # We limit size of inv messaged to 10000 entries
-                        # because they might time out
-                        # in very slow networks (I2P)
-                        pack = random.sample(tuple(to_send), 10000)
-                        self.send_queue.put(message.Inv(pack))
-                        to_send.difference_update(pack)
-                    else:
-                        self.send_queue.put(message.Inv(to_send))
-                        to_send.clear()
+        if shared.objects:
+            for chunk in shared.objects.biginv_chunks(10000):
+                # We limit size of inv messages to 10000 entries
+                # because they might time out in very slow networks (I2P)
+                self.send_queue.put(message.Inv(chunk))
         self.status = 'fully_established'
 
     def _process_queue(self):
@@ -442,7 +431,7 @@ class ConnectionBase(threading.Thread):
 
     def _request_objects(self):
         if self.vectors_to_get and len(self.vectors_requested) < 100:
-            self.vectors_to_get.difference_update(shared.objects.keys())
+            self.vectors_to_get = shared.objects.select(self.vectors_to_get)
             if not self.wait_until:
                 nodes_count = (
                     len(shared.node_pool) + len(shared.unchecked_node_pool))
@@ -489,12 +478,10 @@ class ConnectionBase(threading.Thread):
             else:
                 to_send = self.vectors_to_send.copy()
                 self.vectors_to_send.clear()
-            with shared.objects_lock:
-                for vector in to_send:
-                    obj = shared.objects.get(vector, None)
-                    if obj:
-                        self.send_queue.put(
-                            message.Message(b'object', obj.to_bytes()))
+            for vector in to_send:
+                obj = shared.objects.get(vector)
+                if obj:
+                    self.send_queue.put(message.Message(b'object', obj.data))
 
 
 class Connection(ConnectionBase):
@@ -502,9 +489,7 @@ class Connection(ConnectionBase):
     def _process_msg_inv(self, m):
         inv = message.Inv.from_message(m)
         logging.debug('%s:%s -> %s', self.host_print, self.port, inv)
-        to_get = inv.vectors.copy()
-        to_get.difference_update(shared.objects.keys())
-        self.vectors_to_get.update(to_get)
+        self.vectors_to_get.update(shared.objects.select(inv.vectors))
         # Do not send objects they already have.
         self.vectors_to_send.difference_update(inv.vectors)
 
@@ -513,9 +498,8 @@ class Connection(ConnectionBase):
         logging.debug('%s:%s -> %s', self.host_print, self.port, obj)
         self.vectors_requested.pop(obj.vector, None)
         self.vectors_to_get.discard(obj.vector)
-        if obj.is_valid() and obj.vector not in shared.objects:
-            with shared.objects_lock:
-                shared.objects[obj.vector] = obj
+        if obj.is_valid():
+            shared.objects[obj.vector] = obj
             if (
                 obj.object_type == shared.i2p_dest_obj_type
                 and obj.version == shared.i2p_dest_obj_version
@@ -534,6 +518,7 @@ class Connection(ConnectionBase):
                 logging.debug('Received onion peer object: %s', peer)
                 shared.onion_unchecked_pool.add((peer.host, peer.port))
             shared.vector_advertise_queue.put(obj.vector)
+        shared.objects.check(obj.vector)
 
     def _process_msg_getdata(self, m):
         getdata = message.GetData.from_message(m)
diff --git a/minode/main.py b/minode/main.py
index 050e639..60d2789 100644
--- a/minode/main.py
+++ b/minode/main.py
@@ -15,7 +15,7 @@ try:
 except ImportError:
     socks = None
 
-from . import i2p, shared
+from . import i2p, shared, sql
 from .advertiser import Advertiser
 from .manager import Manager
 from .listener import Listener
@@ -190,10 +190,9 @@ def start_ip_listener():
 def start_i2p_listener():
     """Starts I2P threads"""
     # Grab I2P destinations from old object file
-    for obj in shared.objects.values():
-        if obj.object_type == shared.i2p_dest_obj_type:
-            shared.i2p_unchecked_node_pool.add((
-                base64.b64encode(obj.object_payload, altchars=b'-~'), 'i2p'))
+    for obj in shared.objects.filter(object_type=shared.i2p_dest_obj_type):
+        shared.i2p_unchecked_node_pool.add((
+            base64.b64encode(obj.object_payload, altchars=b'-~'), 'i2p'))
 
     dest_priv = b''
 
@@ -297,6 +296,8 @@ def main():
     elif shared.ip_enabled and not shared.trusted_peer:
         bootstrap_from_dns()
 
+    shared.objects = sql.Inventory()
+
     if shared.i2p_enabled:
         # We are starting it before cleaning expired objects
         # so we can collect I2P destination objects
diff --git a/minode/manager.py b/minode/manager.py
index 1ad9c9b..7d7f31e 100644
--- a/minode/manager.py
+++ b/minode/manager.py
@@ -23,7 +23,6 @@ class Manager(threading.Thread):
         self.bootstrap_pool = []
         self.last_cleaned_objects = time.time()
         self.last_cleaned_connections = time.time()
-        self.last_pickled_objects = time.time()
         self.last_pickled_nodes = time.time()
         # Publish destination 5-15 minutes after start
         self.last_published_i2p_destination = \
@@ -40,23 +39,21 @@ class Manager(threading.Thread):
 
     def run(self):
         self.load_data()
-        self.clean_objects()
+        shared.objects.cleanup()
         self.fill_bootstrap_pool()
         while True:
             time.sleep(0.8)
             now = time.time()
             if shared.shutting_down:
                 logging.debug('Shutting down Manager')
+                shared.objects.flush()
                 break
             if now - self.last_cleaned_objects > 90:
-                self.clean_objects()
+                shared.objects.cleanup()
                 self.last_cleaned_objects = now
             if now - self.last_cleaned_connections > 2:
                 self.manage_connections()
                 self.last_cleaned_connections = now
-            if now - self.last_pickled_objects > 100:
-                self.pickle_objects()
-                self.last_pickled_objects = now
             if now - self.last_pickled_nodes > 60:
                 self.pickle_nodes()
                 self.last_pickled_nodes = now
@@ -67,18 +64,6 @@ class Manager(threading.Thread):
                 self.publish_onion_peer()
                 self.last_published_onion_peer = now
 
-    @staticmethod
-    def clean_objects():
-        """Remove expired objects"""
-        for vector in set(shared.objects):
-            # FIXME: no need to check is_valid() here
-            if shared.objects[vector].is_expired():
-                logging.debug(
-                    'Deleted expired object: %s',
-                    base64.b16encode(vector).decode())
-                with shared.objects_lock:
-                    del shared.objects[vector]
-
     def manage_connections(self):
         """Open new connections if needed, remove closed ones"""
         hosts = set()
@@ -109,6 +94,8 @@ class Manager(threading.Thread):
         outgoing_connections = 0
         for c in shared.connections.copy():
             if not c.is_alive() or c.status == 'disconnected':
+                shared.objects.check(
+                    *(c.vectors_to_get | c.vectors_requested.keys()))
                 with shared.connections_lock:
                     shared.connections.remove(c)
                 try:
@@ -202,17 +189,6 @@ class Manager(threading.Thread):
     @staticmethod
     def load_data():
         """Load initial nodes and data, stored in files between sessions"""
-        try:
-            with open(
-                os.path.join(shared.data_directory, 'objects.pickle'), 'br'
-            ) as src:
-                shared.objects = pickle.load(src)
-        except FileNotFoundError:
-            pass  # first start
-        except Exception:
-            logging.warning(
-                'Error while loading objects from disk.', exc_info=True)
-
         try:
             with open(
                 os.path.join(shared.data_directory, 'nodes.pickle'), 'br'
@@ -263,19 +239,6 @@ class Manager(threading.Thread):
                 (row[0].encode(), 'i2p') for row in reader}
             shared.i2p_node_pool.update(shared.i2p_core_nodes)
 
-    @staticmethod
-    def pickle_objects():
-        """Save objects into a file objects.pickle in the data directory"""
-        try:
-            with open(
-                os.path.join(shared.data_directory, 'objects.pickle'), 'bw'
-            ) as dst:
-                with shared.objects_lock:
-                    pickle.dump(shared.objects, dst, protocol=3)
-                logging.debug('Saved objects')
-        except Exception:
-            logging.warning('Error while saving objects', exc_info=True)
-
     @staticmethod
     def pickle_nodes():
         """Save nodes into files in the data directory"""
diff --git a/minode/proofofwork.py b/minode/proofofwork.py
index 75a2da4..bb5d44a 100644
--- a/minode/proofofwork.py
+++ b/minode/proofofwork.py
@@ -54,9 +54,8 @@ def _worker(obj):
     logging.debug(
         'Object vector is %s', base64.b16encode(obj.vector).decode())
 
-    with shared.objects_lock:
-        shared.objects[obj.vector] = obj
-        shared.vector_advertise_queue.put(obj.vector)
+    shared.objects[obj.vector] = obj
+    shared.vector_advertise_queue.put(obj.vector)
 
 
 def do_pow_and_publish(obj):
diff --git a/minode/shared.py b/minode/shared.py
index bbdce1a..84e0456 100644
--- a/minode/shared.py
+++ b/minode/shared.py
@@ -21,7 +21,7 @@ protocol_version = 3
 services = 3  # NODE_NETWORK, NODE_SSL
 stream = 1
 nonce = os.urandom(8)
-user_agent = b'/MiNode:0.3.4/'
+user_agent = b'/MiNode:0.3.5/'
 timeout = 600
 header_length = 24
 i2p_dest_obj_type = 0x493250
@@ -73,4 +73,3 @@ outgoing_connections = 8
 connection_limit = 250
 
 objects = {}
-objects_lock = threading.Lock()
diff --git a/minode/sql.py b/minode/sql.py
new file mode 100644
index 0000000..8e36c9e
--- /dev/null
+++ b/minode/sql.py
@@ -0,0 +1,257 @@
+"""Inventory implementation using sqlite"""
+
+import base64
+import logging
+import os
+import sqlite3
+import threading
+import time
+
+from . import shared, structure
+
+sqlite3.threadsafety = 3
+
+
+class Inventory():
+    """sqlite inventory"""
+    def __init__(self):
+        self._lock = threading.Lock()
+        self._deleted = 0
+        self._last = {}
+        self._pending = set()
+        self._db = sqlite3.connect(
+            os.path.join(shared.data_directory, 'objects.dat'),
+            check_same_thread=False
+        )
+        self._db.executescript("""
+        BEGIN;
+        CREATE TABLE IF NOT EXISTS status
+        (key text, value integer, UNIQUE(key) ON CONFLICT REPLACE);
+        INSERT INTO status VALUES ('version', 1);
+        CREATE TABLE IF NOT EXISTS objects
+        (vector unique, expires integer, type integer, version integer,
+        stream integer, tag, data, offset integer);
+        COMMIT;
+        """)
+        self.rowid = len(self) or None
+        try:
+            self.lastvacuumtime = self._db.execute(
+                "SELECT value FROM status WHERE key='lastvacuumtime'"
+            ).fetchone()[0]
+        except TypeError:
+            self.lastvacuumtime = int(time.time())
+            self._db.execute(
+                "INSERT INTO status VALUES ('lastvacuumtime', ?)",
+                (self.lastvacuumtime,)
+            )
+        self._db.commit()
+        self._db.row_factory = self.__object
+
+    @staticmethod
+    def __object(cursor, row):
+        if len(cursor.description) != 8:
+            return row
+        vector, expires, obj_type, version, stream, tag, data, offset = row
+        return structure.Object(
+            expires, obj_type, version, stream,
+            data=data, offset=offset, tag=tag, vector=vector)
+
+    def check(self, *vectors):
+        """Remove given vectors from pending"""
+        with self._lock:
+            for vector in vectors:
+                self._pending.discard(vector)
+
+    def cleanup(self):
+        """Remove expired objects"""
+        if len(self._pending) > 100:
+            logging.info(
+                'Not cleaning up, %s objects pending', len(self._pending))
+            return
+        for vector in set(self._last):
+            if self._last[vector].is_expired():
+                logging.debug(
+                    'Deleted expired object: %s',
+                    base64.b16encode(vector).decode())
+                with self._lock:
+                    del self._last[vector]
+        if len(self._last) > 1000:
+            self.flush()
+            return
+        with self._lock:
+            now = int(time.time())
+            cur = self._db.execute(
+                'DELETE FROM objects WHERE expires < ?', (now - 3 * 3600,))
+            self._db.commit()
+            self._deleted += cur.rowcount
+            (logging.info if self._pending else logging.debug)(
+                'Deleted %s expired objects, %s pending',
+                cur.rowcount, len(self._pending))
+            # conditional vacuum and validity check (TODO)
+            # every 24 hours or after deleting a lot of items
+            if self._deleted > 10000 or self.lastvacuumtime < now - 86400:
+                logging.info('Doing VACUUM for objects')
+                cur.execute('VACUUM')
+                cur.execute(
+                    "INSERT INTO status VALUES ('lastvacuumtime', ?)", (now,))
+                self._db.commit()
+                self._deleted = 0
+                self.lastvacuumtime = now
+
+    def flush(self):
+        """Write cached objects to the database"""
+        with self._lock:
+            cur = self._db.executemany(
+                'INSERT INTO objects VALUES (?,?,?,?,?,?,?,?)',
+                ((obj.vector, obj.expires_time, obj.object_type,
+                  obj.version, obj.stream_number, obj.tag, obj.data,
+                  obj.offset) for obj in self._last.values()))
+            self._db.commit()
+            self.rowid = cur.lastrowid
+            self._last = {}
+
+    def filter(self, stream=None, object_type=None, tag=None):
+        """Generator of objects with the given parameters"""
+        def fits(obj):
+            if stream and obj.stream_number != stream:
+                return False
+            if object_type is not None and obj.object_type != object_type:
+                return False
+            if tag and obj.tag != tag:
+                return False
+            return True
+
+        yield from filter(fits, self._last.values())
+
+        clauses = []
+        if stream:
+            clauses.append(('stream = ?', stream))
+        if object_type is not None:
+            clauses.append(('type = ?', object_type))
+        if tag:
+            clauses.append(('tag = ?', tag))
+
+        clauses, params = zip(*clauses)
+
+        yield from self._db.execute(
+            'SELECT * FROM objects WHERE '  # nosec B608
+            + ' AND '.join(clauses), params)
+
+    def select(self, vectors):
+        """Select new vectors from the given set"""
+        chunk_size = 999
+        with self._lock:
+            vectors.difference_update(self._last)
+            keys = tuple(vectors)
+            for i in range(0, len(vectors), chunk_size):
+                chunk = keys[i:i+chunk_size]
+                cur = self._db.execute(
+                    'SELECT vector FROM objects WHERE vector IN'  # nosec B608
+                    ' ({})'.format(','.join('?' * len(chunk))),
+                    chunk)
+                for v, in cur:
+                    vectors.remove(v)
+            self._pending.update(vectors)
+        return vectors
+
+    def biginv_chunks(self, chunk_size=10000, stream=None):
+        """Generator of vector lists for making the biginv"""
+        if stream is None:
+            stream = shared.stream
+        now = int(time.time())
+        cur = self._db.execute(
+            'SELECT vector FROM objects WHERE expires > ? AND stream = ?'
+            ' ORDER BY random()', (now, stream)
+        )
+        cur.arraysize = chunk_size
+        while True:
+            vectors = cur.fetchmany()
+            if not vectors:
+                # TODO: append to the last short result,
+                # check that _last is shorter than the chunk_size
+                # (should be < 1000)
+                if self._last:
+                    yield [
+                        obj.vector for obj in self._last.values()
+                        if obj.stream_number == stream
+                        and obj.expires_time > now]
+                return
+            yield [v for v, in vectors]
+
+    def get(self, vector, default=None):
+        try:
+            return self[vector]
+        except KeyError:
+            return default
+
+    def keys(self):
+        yield from self._last
+        for vector, in self._db.execute('SELECT vector FROM objects'):
+            yield vector
+
+    def values(self):
+        yield from self._last.values()
+        yield from self._db.execute('SELECT * FROM objects')
+
+    def popitem(self):
+        try:
+            return self._last.popitem()
+        except KeyError:
+            pass
+        if not self.rowid:
+            raise KeyError('empty')
+        cur = self._db.execute(
+            'SELECT vector FROM objects WHERE ROWID = ?', (self.rowid,))
+        vector = cur.fetchone()[0]
+        obj = self.get(vector)
+        del self[vector]
+        return (vector, obj)
+
+    def __contains__(self, vector):
+        if vector in self._last:
+            return True
+        return self._db.execute(
+            'SELECT vector FROM objects WHERE vector = ?', (vector,)
+        ).fetchone() is not None
+
+    def __getitem__(self, vector):
+        try:
+            return self._last[vector]
+        except KeyError:
+            pass
+        item = self._db.execute(
+            'SELECT * FROM objects WHERE vector = ?', (vector,)).fetchone()
+        if item is None:
+            raise KeyError(vector)
+        return item
+
+    def __delitem__(self, vector):
+        try:
+            del self._last[vector]
+            return
+        except KeyError:
+            pass
+        with self._lock:  # KeyError
+            self._db.execute('DELETE FROM objects WHERE vector = ?', (vector,))
+            self._db.commit()
+            self.rowid = len(self)
+
+    def __setitem__(self, vector, obj):
+        if vector in self:
+            return
+        with self._lock:
+            self._last[vector] = obj
+
+    def __bool__(self):
+        if self._last:
+            return True
+        return self._db.execute(
+            'SELECT vector from objects LIMIT 1').fetchone() is not None
+
+    def __len__(self):
+        cur = self._db.execute('SELECT count(*) FROM objects')
+        return cur.fetchone()[0] + len(self._last)
+
+    def __del__(self):
+        self.flush()
+        self._db.close()
diff --git a/minode/structure.py b/minode/structure.py
index 77d3d0b..2cd5c5b 100644
--- a/minode/structure.py
+++ b/minode/structure.py
@@ -65,20 +65,25 @@ class Object():
     """The 'object' message payload"""
     def __init__(
         self, expires_time, object_type, version, stream_number,
-        *, object_payload, tag=None, nonce=b'\x00' * 8
+        *, data=None, offset=None, object_payload=None,
+        tag=None, nonce=b'\x00' * 8, vector=None
     ):
         self.nonce = nonce
         self.expires_time = expires_time
         self.object_type = object_type
         self.version = version
         self.stream_number = stream_number
-        self.object_payload = object_payload
-        self.vector = hashlib.sha512(hashlib.sha512(
-            self.to_bytes()).digest()).digest()[:32]
+        if not data:
+            data, offset = self.to_bytes(object_payload)
+        self.data = data
+        self.offset = offset
+        self.vector = vector or hashlib.sha512(hashlib.sha512(
+            self.data).digest()).digest()[:32]
 
         self.tag = tag or (
             # broadcast from version 5 and pubkey/getpukey from version 4
-            self.object_payload[:32] if object_type == 3 and version == 5
+            (object_payload or self.object_payload)[:32]
+            if object_type == 3 and version == 5
             or (object_type in (0, 1) and version == 4)
             else None)
 
@@ -89,30 +94,33 @@ class Object():
     @classmethod
     def from_message(cls, m):
         """Decode message payload"""
-        payload = m.payload
-        nonce, expires_time, object_type = struct.unpack('>8sQL', payload[:20])
-        payload = payload[20:]
-        version_varint_length = VarInt.length(payload[0])
-        version = VarInt.from_bytes(payload[:version_varint_length]).n
-        payload = payload[version_varint_length:]
-        stream_number_varint_length = VarInt.length(payload[0])
+        data = m.payload
+        nonce, expires_time, object_type = struct.unpack('>8sQL', data[:20])
+        version_varint_length = VarInt.length(data[20])
+        offset = 20 + version_varint_length
+        version = VarInt.from_bytes(data[20:offset]).n
+        stream_number_varint_length = VarInt.length(data[offset])
         stream_number = VarInt.from_bytes(
-            payload[:stream_number_varint_length]).n
-        payload = payload[stream_number_varint_length:]
+            data[offset:offset+stream_number_varint_length]).n
+        offset += stream_number_varint_length
         return cls(
             expires_time, object_type, version, stream_number,
-            object_payload=payload, nonce=nonce)
+            data=data, offset=offset, nonce=nonce
+        )
 
-    def to_bytes(self):
-        """Serialize to bytes object payload"""
+    @property
+    def object_payload(self):
+        return self.data[self.offset:]
+
+    def to_bytes(self, object_payload):
+        """Serialize to bytes"""
         payload = b''
         payload += self.nonce
         payload += struct.pack('>QL', self.expires_time, self.object_type)
         payload += (
             VarInt(self.version).to_bytes()
             + VarInt(self.stream_number).to_bytes())
-        payload += self.object_payload
-        return payload
+        return payload + object_payload, len(payload)
 
     def is_expired(self):
         """Check if object's TTL is expired"""
@@ -155,7 +163,7 @@ class Object():
 
     def pow_target(self):
         """Compute PoW target"""
-        data = self.to_bytes()[8:]
+        data = self.data[8:]
         length = len(data) + 8 + shared.payload_length_extra_bytes
         dt = max(self.expires_time - time.time(), 0)
         return int(
@@ -165,7 +173,7 @@ class Object():
 
     def pow_initial_hash(self):
         """Compute the initial hash for PoW"""
-        return hashlib.sha512(self.to_bytes()[8:]).digest()
+        return hashlib.sha512(self.data[8:]).digest()
 
 
 class NetAddrNoPrefix(IStructure):
diff --git a/minode/tests/test_network.py b/minode/tests/test_network.py
index c683637..1a9085e 100644
--- a/minode/tests/test_network.py
+++ b/minode/tests/test_network.py
@@ -8,7 +8,7 @@ import tempfile
 import time
 from contextlib import contextmanager
 
-from minode import connection, main, shared
+from minode import connection, main, shared, sql
 from minode.listener import Listener
 from minode.manager import Manager
 
@@ -66,11 +66,14 @@ class TestNetwork(unittest.TestCase):
     def setUp(self):
         shared.core_nodes.clear()
         shared.unchecked_node_pool.clear()
-        shared.objects = {}
         try:
-            os.remove(os.path.join(shared.data_directory, 'objects.pickle'))
+            os.remove(os.path.join(shared.data_directory, 'objects.dat'))
         except FileNotFoundError:
             pass
+        shared.objects = sql.Inventory()
+
+    def tearDown(self):
+        shared.objects.flush()
 
     def _make_initial_nodes(self):
         Manager.load_data()
diff --git a/minode/tests/test_objects.py b/minode/tests/test_objects.py
new file mode 100644
index 0000000..fe2b825
--- /dev/null
+++ b/minode/tests/test_objects.py
@@ -0,0 +1,165 @@
+"""Tests for the Inventory implementation"""
+import os
+import random
+import tempfile
+import time
+import unittest
+
+from minode import sql, shared, structure
+
+
+# + __bool__
+# + __contains__
+# + __getitem__
+# + __setitem__
+# = cleanup
+# + get
+# + filter
+# = select
+# + biginv_chunks
+
+
+class TestObjects():
+    """
+    A base class for the test case for shared.objects,
+    containing tests for all the methods directly used in code.
+    """
+    # pylint: disable=no-member
+    # A possibility of abstract test cases was rejected:
+    # https://bugs.python.org/issue17519
+
+    def test_set_get(self):
+        """Put some objects and check presence and getting"""
+        obj = structure.Object(
+            int(time.time()), 42, 1, 1, object_payload=b'HELLO')
+        self.assertFalse(obj.vector in self.objects)
+        with self.assertRaises(KeyError):
+            self.objects[obj.vector]  # pylint: disable=pointless-statement
+        self.assertIsNone(self.objects.get(obj.vector))
+        prev_len = len(self.objects)
+        self.objects[obj.vector] = obj
+        self.objects[obj.vector] = obj
+        self.assertTrue(self.objects)
+        self.assertEqual(len(self.objects), prev_len + 1)
+        self.assertTrue(obj.vector in self.objects)
+        obj1 = self.objects[obj.vector]
+        self.assertEqual(obj.vector, obj1.vector)
+        self.assertEqual(obj.data, obj1.data)
+
+    def test_biginv_chunks(self):
+        """Check vectors_to_send method"""
+        needed = set()
+        for _ in range(10):
+            # wrong stream
+            obj = structure.Object(
+                int(time.time()) + 10, 42, 1, random.randint(1, 3),
+                object_payload=os.urandom(32))
+            self.objects[obj.vector] = obj
+            # expired
+            obj = structure.Object(
+                int(time.time()) - 10, 42, 1, 4, object_payload=os.urandom(32))
+            self.objects[obj.vector] = obj
+            # interesting
+            obj = structure.Object(
+                int(time.time()) + 10, 42, 1, 4, object_payload=os.urandom(32))
+            self.objects[obj.vector] = obj
+            needed.add(obj.vector)
+
+        self.assertEqual(
+            set(next(self.objects.biginv_chunks(stream=4))), needed)
+        self.assertTrue(
+            set(next(self.objects.biginv_chunks())).difference(needed))
+
+    def test_filter(self):
+        """Check the objects filtering"""
+        needed = set()
+        tagged = set()
+        tag = b'@' * 32
+        for _ in range(10):
+            # wrong type
+            obj = structure.Object(
+                int(time.time()), 0, 1, 5, object_payload=os.urandom(64))
+            self.objects[obj.vector] = obj
+            # wrong type, but the proper tag
+            obj = structure.Object(
+                int(time.time()) - 11000, 0, 4, random.choice([1, 2, 3, 5]),
+                object_payload=tag + os.urandom(32))
+            self.objects[obj.vector] = obj
+            tagged.add(obj.vector)
+            # wrong stream
+            obj = structure.Object(
+                int(time.time()), 33, 1, 1, object_payload=os.urandom(32))
+            self.objects[obj.vector] = obj
+            # interesting
+            obj = structure.Object(
+                int(time.time()) - 11000, 33, 1, 5,
+                object_payload=os.urandom(32))
+            self.objects[obj.vector] = obj
+            needed.add(obj.vector)
+
+        # stream and type
+        self.assertTrue(needed)
+        for obj in self.objects.filter(5, 33):
+            needed.remove(obj.vector)
+        self.assertFalse(needed)
+
+        # tag
+        self.assertTrue(tagged)
+        for obj in self.objects.filter(tag=tag):
+            tagged.remove(obj.vector)
+        self.assertFalse(tagged)
+
+    def test_cleanup(self):
+        """Check cleaning up"""
+        for _ in range(10):
+            obj = structure.Object(
+                int(time.time()) - random.randint(4, 5) * 3600,
+                42, 1, 6, object_payload=os.urandom(32))
+            self.objects[obj.vector] = obj
+            obj = structure.Object(
+                int(time.time()) - 2 * 3600,
+                42, 1, 6, object_payload=os.urandom(32))
+            self.objects[obj.vector] = obj
+
+        for obj in self.objects.values():
+            if obj.is_expired():
+                break
+        else:
+            self.fail('No objects found to delete')
+
+        self.objects.cleanup()
+        self.assertTrue(self.objects)
+        for obj in self.objects.values():
+            self.assertFalse(obj.is_expired())
+
+    def test_select(self):
+        """Check the select method"""
+        pending = set()
+        questionable = set()
+
+        for _ in range(5):
+            obj = structure.Object(
+                int(time.time()) - 10, 42, 1, 7, object_payload=os.urandom(32))
+            questionable.add(obj.vector)
+            self.objects[obj.vector] = obj
+            obj = structure.Object(
+                int(time.time()) + 10, 42, 1, 7, object_payload=os.urandom(32))
+            questionable.add(obj.vector)
+            pending.add(obj.vector)
+
+        self.assertEqual(self.objects.select(questionable), pending)
+
+
+class TestObjectsSQL(TestObjects, unittest.TestCase):
+    """A test case for the sqlite inventory"""
+
+    @classmethod
+    def setUpClass(cls):
+        shared.data_directory = tempfile.gettempdir()
+        cls.tearDownClass()
+        cls.objects = sql.Inventory()
+
+    @classmethod
+    def tearDownClass(cls):
+        cls.objects = None
+        os.remove(os.path.join(shared.data_directory, 'objects.dat'))
diff --git a/minode/tests/test_structure.py b/minode/tests/test_structure.py
index fef8a5c..ff83849 100644
--- a/minode/tests/test_structure.py
+++ b/minode/tests/test_structure.py
@@ -16,11 +16,12 @@ sample_addr_data = unhexlify(
     '260753000201300000000000000057ae1f90')
 
 # data for an object with expires_time 1697063939
-# structure.Object(
-#     expires_time, 42, 1, 2, object_payload=b'HELLO').to_bytes()
+# structure.Object(expires_time, 42, 1, 2, object_payload=b'HELLO').data
 sample_object_data = unhexlify(
     '000000000000000000000000652724030000002a010248454c4c4f')
 
+sample_object_expires = 1697063939
+
 sample_onion_host = \
     'bmtestlmgmvpbsg7kzmrxu47chs3cdou2tj4t5iloocgujzsf3e7rbqd.onion'
 
@@ -132,9 +133,16 @@ class TestStructure(unittest.TestCase):
             message.Message(b'object', sample_object_data))
         self.assertEqual(obj.object_type, 42)
         self.assertEqual(obj.stream_number, 2)
-        self.assertEqual(obj.expires_time, 1697063939)
+        self.assertEqual(obj.expires_time, sample_object_expires)
         self.assertEqual(obj.object_payload, b'HELLO')
 
+        obj = structure.Object(
+            sample_object_expires, 42, 1, 2, object_payload=b'HELLO')
+        self.assertEqual(obj.data, sample_object_data)
+        self.assertEqual(obj.offset, 22)
+        self.assertEqual(obj.nonce, b'\x00' * 8)
+        self.assertTrue(obj.is_expired())
+
         obj = structure.Object(
             int(time.time() + 3000000), 42, 1, 1, object_payload=b'HELLO')
         self.assertFalse(obj.is_valid())
@@ -152,9 +160,10 @@ class TestStructure(unittest.TestCase):
         shared.stream = 2
         self.assertTrue(obj.is_valid())
 
-        obj.object_payload = \
-            b'TIGER, tiger, burning bright. In the forests of the night'
-        self.assertFalse(obj.is_valid())
+        # obj.data = struct.pack(...
+        # obj.object_payload = \
+        #     b'TIGER, tiger, burning bright. In the forests of the night'
+        # self.assertFalse(obj.is_valid())
 
     def test_onion_peer(self):
         """Make an onion peer object and decode it back"""