diff --git a/mitmproxy/addons/session.py b/mitmproxy/addons/session.py
index c08097ee8..f9d3af3fa 100644
--- a/mitmproxy/addons/session.py
+++ b/mitmproxy/addons/session.py
@@ -1,9 +1,11 @@
+import collections
 import tempfile
 import asyncio
 import typing
 import bisect
 import shutil
 import sqlite3
+import copy
 import os
 
 from mitmproxy import flowfilter
@@ -48,6 +50,7 @@ class SessionDB:
         or create a new one with optional path.
         :param db_path:
         """
+        self.live_components = {}
         self.tempdir = None
         self.con = None
         # This is used for fast look-ups over bodies already dumped to database.
@@ -71,11 +74,14 @@ class SessionDB:
             shutil.rmtree(self.tempdir)
 
     def __contains__(self, fid):
-        return fid in self._get_ids()
+        return any([fid == i for i in self._get_ids()])
+
+    def __len__(self):
+        ln = self.con.execute("SELECT COUNT(*) FROM flow;").fetchall()[0]
+        return ln[0] if ln else 0
 
     def _get_ids(self):
-        with self.con as con:
-            return [t[0] for t in con.execute("SELECT id FROM flow;").fetchall()]
+        return [t[0] for t in self.con.execute("SELECT id FROM flow;").fetchall()]
 
     def _load_session(self, path):
         if not self.is_session_db(path):
@@ -85,8 +91,8 @@ class SessionDB:
     def _create_session(self):
         script_path = pkg_data.path("io/sql/session_create.sql")
         qry = open(script_path, 'r').read()
-        with self.con:
-            self.con.executescript(qry)
+        self.con.executescript(qry)
+        self.con.commit()
 
     @staticmethod
     def is_session_db(path):
@@ -110,62 +116,104 @@ class SessionDB:
                 c.close()
         return False
 
+    def _disassemble(self, flow):
+        # Some live components of flows cannot be serialized, but they are needed to ensure correct functionality.
+        # We solve this by keeping a list of tuples which "save" those components for each flow id, eventually
+        # adding them back when needed.
+        self.live_components[flow.id] = (
+            flow.client_conn.wfile,
+            flow.client_conn.rfile,
+            flow.client_conn.reply,
+            flow.server_conn.wfile,
+            flow.server_conn.rfile,
+            flow.server_conn.reply,
+            (flow.server_conn.via.wfile, flow.server_conn.via.rfile,
+             flow.server_conn.via.reply) if flow.server_conn.via else None,
+            flow.reply
+        )
+
+    def _reassemble(self, flow):
+        if flow.id in self.live_components:
+            cwf, crf, crp, swf, srf, srp, via, rep = self.live_components[flow.id]
+            flow.client_conn.wfile = cwf
+            flow.client_conn.rfile = crf
+            flow.client_conn.reply = crp
+            flow.server_conn.wfile = swf
+            flow.server_conn.rfile = srf
+            flow.server_conn.reply = srp
+            flow.reply = rep
+            if via:
+                flow.server_conn.via.rfile, flow.server_conn.via.wfile, flow.server_conn.via.reply = via
+        return flow
+
     def store_flows(self, flows):
         body_buf = []
         flow_buf = []
         for flow in flows:
-            if len(flow.request.content) > self.content_threshold:
-                body_buf.append((flow.id, self.type_mappings["body"][1], flow.request.content))
-                flow.request.content = b""
-                self.body_ledger.add(flow.id)
-            if flow.response and flow.id not in self.body_ledger:
-                if len(flow.response.content) > self.content_threshold:
-                    body_buf.append((flow.id, self.type_mappings["body"][2], flow.response.content))
-                    flow.response.content = b""
-            flow_buf.append((flow.id, protobuf.dumps(flow)))
-        with self.con as con:
-            con.executemany("INSERT OR REPLACE INTO flow VALUES(?, ?)", flow_buf)
-            con.executemany("INSERT INTO body VALUES(?, ?, ?)", body_buf)
+            self._disassemble(flow)
+            f = copy.copy(flow)
+            f.request = copy.deepcopy(flow.request)
+            if flow.response:
+                f.response = copy.deepcopy(flow.response)
+            f.id = flow.id
+            if len(f.request.content) > self.content_threshold and f.id not in self.body_ledger:
+                body_buf.append((f.id, 1, f.request.content))
+                f.request.content = b""
+                self.body_ledger.add(f.id)
+            if f.response and f.id not in self.body_ledger:
+                if len(f.response.content) > self.content_threshold:
+                    body_buf.append((f.id, 2, f.response.content))
+                    f.response.content = b""
+            flow_buf.append((f.id, protobuf.dumps(f)))
+        self.con.executemany("INSERT OR REPLACE INTO flow VALUES(?, ?);", flow_buf)
+        if body_buf:
+            self.con.executemany("INSERT INTO body (flow_id, type_id, content) VALUES(?, ?, ?);", body_buf)
+        self.con.commit()
 
     def retrieve_flows(self, ids=None):
         flows = []
         with self.con as con:
             if not ids:
                 sql = "SELECT f.content, b.type_id, b.content " \
-                      "FROM flow f, body b " \
-                      "WHERE f.id = b.flow_id;"
+                      "FROM flow f " \
+                      "LEFT OUTER JOIN body b ON f.id = b.flow_id;"
                 rows = con.execute(sql).fetchall()
             else:
                 sql = "SELECT f.content, b.type_id, b.content " \
-                      "FROM flow f, body b " \
-                      "WHERE f.id = b.flow_id" \
-                      f"AND f.id IN ({','.join(['?' for _ in range(len(ids))])})"
+                      "FROM flow f " \
+                      "LEFT OUTER JOIN body b ON f.id = b.flow_id " \
+                      f"AND f.id IN ({','.join(['?' for _ in range(len(ids))])});"
                 rows = con.execute(sql, ids).fetchall()
             for row in rows:
                 flow = protobuf.loads(row[0])
-                typ = self.type_mappings["body"][row[1]]
-                if typ and row[2]:
-                    setattr(getattr(flow, typ), "content", row[2])
+                if row[1]:
+                    typ = self.type_mappings["body"][row[1]]
+                    if typ and row[2]:
+                        setattr(getattr(flow, typ), "content", row[2])
+                flow = self._reassemble(flow)
                 flows.append(flow)
         return flows
 
+    def clear(self):
+        self.con.executescript("DELETE FROM body; DELETE FROM annotation; DELETE FROM flow;")
+
 
 matchall = flowfilter.parse(".")
 
 orders = [
-    ("t", "time"),
-    ("m", "method"),
-    ("u", "url"),
-    ("z", "size")
+    "time",
+    "method",
+    "url",
+    "size"
 ]
 
 
 class Session:
     def __init__(self):
-        self.dbstore = SessionDB(ctx.options.session_path)
-        self._hot_store = []
-        self._view = []
+        self.db_store = None
+        self._hot_store = collections.OrderedDict()
         self._live_components = {}
+        self._view = []
         self.order = orders[0]
         self.filter = matchall
         self._flush_period = 3.0
@@ -191,6 +239,7 @@ class Session:
     def running(self):
         if not self.started:
             self.started = True
+            self.db_store = SessionDB(ctx.options.session_path)
             loop = asyncio.get_event_loop()
             tasks = (self._writer, self._tweaker)
             loop.create_task(asyncio.gather(*(t() for t in tasks)))
@@ -201,6 +250,60 @@ class Session:
         if "view_filter" in updated:
             self.set_filter(ctx.options.view_filter)
 
+    async def _writer(self):
+        while True:
+            await asyncio.sleep(self._flush_period)
+            tof = []
+            to_dump = min(self._flush_rate, len(self._hot_store))
+            for _ in range(to_dump):
+                tof.append(self._hot_store.popitem(last=False)[1])
+            self.db_store.store_flows(tof)
+
+    async def _tweaker(self):
+        while True:
+            await asyncio.sleep(self._tweak_period)
+            if len(self._hot_store) >= 3 * self._flush_rate:
+                self._flush_period *= 0.9
+                self._flush_rate *= 1.1
+            elif len(self._hot_store) < self._flush_rate:
+                self._flush_period *= 1.1
+                self._flush_rate *= 0.9
+
+    def load_view(self, ids=None):
+        flows = []
+        ids_from_store = []
+        if ids is None:
+            ids = [fid for _, fid in self._view]
+        for fid in ids:
+            # Flow could be at the same time in database and in hot storage. We want the most updated version.
+            if fid in self._hot_store:
+                flows.append(self._hot_store[fid])
+            elif fid in self.db_store:
+                ids_from_store.append(fid)
+            else:
+                flows.append(None)
+        flows += self.db_store.retrieve_flows(ids_from_store)
+        return flows
+
+    def load_storage(self):
+        flows = []
+        flows += self.db_store.retrieve_flows()
+        for flow in self._hot_store.values():
+            flows.append(flow)
+        return flows
+
+    def clear_storage(self):
+        self.db_store.clear()
+        self._hot_store.clear()
+        self._view = []
+
+    def store_count(self):
+        ln = 0
+        for fid in self._hot_store.keys():
+            if fid not in self.db_store:
+                ln += 1
+        return ln + len(self.db_store)
+
     def _generate_order(self, f: http.HTTPFlow) -> typing.Union[str, int, float]:
         o = self.order
         if o == "time":
@@ -225,19 +328,19 @@ class Session:
         if order != self.order:
             self.order = order
             newview = [
-                (self._generate_order(f), f.id) for f in self.dbstore.retrieve_flows([t[0] for t in self._view])
+                (self._generate_order(f), f.id) for f in self.load_view()
             ]
             self._view = sorted(newview)
 
     def _refilter(self):
         self._view = []
-        flows = self.dbstore.retrieve_flows()
+        flows = self.load_storage()
         for f in flows:
             if self.filter(f):
                 self._base_add(f)
 
-    def set_filter(self, input_filter: str) -> None:
-        filt = flowfilter.parse(input_filter)
+    def set_filter(self, input_filter: typing.Optional[str]) -> None:
+        filt = matchall if not input_filter else flowfilter.parse(input_filter)
         if not filt:
             raise CommandError(
                 "Invalid interception filter: %s" % filt
@@ -245,54 +348,21 @@ class Session:
         self.filter = filt
         self._refilter()
 
-    async def _writer(self):
-        while True:
-            await asyncio.sleep(self._flush_period)
-            tof = []
-            to_dump = min(self._flush_rate, len(self._hot_store))
-            for _ in range(to_dump):
-                tof.append(self._hot_store.pop())
-            self.store(tof)
-
-    async def _tweaker(self):
-        while True:
-            await asyncio.sleep(self._tweak_period)
-            if len(self._hot_store) >= self._flush_rate:
-                self._flush_period *= 0.9
-                self._flush_rate *= 0.9
-            elif len(self._hot_store) < self._flush_rate:
-                self._flush_period *= 1.1
-                self._flush_rate *= 1.1
-
-    def store(self, flows: typing.Sequence[http.HTTPFlow]) -> None:
-        # Some live components of flows cannot be serialized, but they are needed to ensure correct functionality.
-        # We solve this by keeping a list of tuples which "save" those components for each flow id, eventually
-        # adding them back when needed.
-        for f in flows:
-            self._live_components[f.id] = (
-                f.client_conn.wfile or None,
-                f.client_conn.rfile or None,
-                f.server_conn.wfile or None,
-                f.server_conn.rfile or None,
-                f.reply or None
-            )
-        self.dbstore.store_flows(flows)
-
     def _base_add(self, f):
-        if f.id not in self._view:
+        if not any([f.id == t[1] for t in self._view]):
             o = self._generate_order(f)
             self._view.insert(bisect.bisect_left(KeyifyList(self._view, lambda x: x[0]), o), (o, f.id))
         else:
             o = self._generate_order(f)
-            self._view = [flow for flow in self._view if flow.id != f.id]
+            self._view = [(order, fid) for order, fid in self._view if fid != f.id]
             self._view.insert(bisect.bisect_left(KeyifyList(self._view, lambda x: x[0]), o), (o, f.id))
 
     def update(self, flows: typing.Sequence[http.HTTPFlow]) -> None:
         for f in flows:
+            if f.id in self._hot_store:
+                self._hot_store.pop(f.id)
+            self._hot_store[f.id] = f
             if self.filter(f):
-                if f.id in [f.id for f in self._hot_store]:
-                    self._hot_store = [flow for flow in self._hot_store if flow.id != f.id]
-                self._hot_store.append(f)
                 self._base_add(f)
 
     def request(self, f):
diff --git a/test/mitmproxy/addons/test_session.py b/test/mitmproxy/addons/test_session.py
index d4b1109b0..41e8a4014 100644
--- a/test/mitmproxy/addons/test_session.py
+++ b/test/mitmproxy/addons/test_session.py
@@ -1,13 +1,37 @@
 import sqlite3
+import asyncio
 import pytest
 import os
 
+from mitmproxy import ctx
+from mitmproxy import http
+from mitmproxy.test import tflow, tutils
+from mitmproxy.test import taddons
 from mitmproxy.addons import session
-from mitmproxy.exceptions import SessionLoadException
+from mitmproxy.exceptions import SessionLoadException, CommandError
 from mitmproxy.utils.data import pkg_data
 
 
 class TestSession:
+
+    @staticmethod
+    def tft(*, method="GET", start=0):
+        f = tflow.tflow()
+        f.request.method = method
+        f.request.timestamp_start = start
+        return f
+
+    @staticmethod
+    def start_session(fp=None):
+        s = session.Session()
+        tctx = taddons.context()
+        tctx.master.addons.add(s)
+        tctx.options.session_path = None
+        if fp:
+            s._flush_period = fp
+        s.running()
+        return s
+
     def test_session_temporary(self):
         s = session.SessionDB()
         td = s.tempdir
@@ -56,3 +80,130 @@ class TestSession:
             assert len(rows) == 1
         con.close()
         os.remove(path)
+
+    def test_session_order_generators(self):
+        s = session.Session()
+        tf = tflow.tflow(resp=True)
+
+        s.order = "time"
+        assert s._generate_order(tf) == 946681200
+
+        s.order = "method"
+        assert s._generate_order(tf) == tf.request.method
+
+        s.order = "url"
+        assert s._generate_order(tf) == tf.request.url
+
+        s.order = "size"
+        assert s._generate_order(tf) == len(tf.request.raw_content) + len(tf.response.raw_content)
+
+    def test_simple(self):
+        s = session.Session()
+        ctx.options = taddons.context()
+        ctx.options.session_path = None
+        s.running()
+        f = self.tft(start=1)
+        assert s.store_count() == 0
+        s.request(f)
+        assert s._view == [(1, f.id)]
+        assert s.load_view([f.id]) == [f]
+        assert s.load_view(['nonexistent']) == [None]
+
+        s.error(f)
+        s.response(f)
+        s.intercept(f)
+        s.resume(f)
+        s.kill(f)
+
+        # Verify that flow has been updated, not duplicated
+        assert s._view == [(1, f.id)]
+        assert s.store_count() == 1
+
+        f2 = self.tft(start=3)
+        s.request(f2)
+        assert s._view == [(1, f.id), (3, f2.id)]
+        s.request(f2)
+        assert s._view == [(1, f.id), (3, f2.id)]
+
+        f3 = self.tft(start=2)
+        s.request(f3)
+        assert s._view == [(1, f.id), (2, f3.id), (3, f2.id)]
+        s.request(f3)
+        assert s._view == [(1, f.id), (2, f3.id), (3, f2.id)]
+        assert s.store_count() == 3
+
+        s.clear_storage()
+        assert len(s._view) == 0
+        assert s.store_count() == 0
+
+    def test_filter(self):
+        s = self.start_session()
+        s.request(self.tft(method="get"))
+        s.request(self.tft(method="put"))
+        s.request(self.tft(method="get"))
+        s.request(self.tft(method="put"))
+        assert len(s._view) == 4
+        s.set_filter("~m get")
+        assert [f.request.method for f in s.load_view()] == ["GET", "GET"]
+        assert s.store_count() == 4
+        with pytest.raises(CommandError):
+            s.set_filter("~notafilter")
+        s.set_filter(None)
+        assert len(s._view) == 4
+
+    @pytest.mark.asyncio
+    async def test_flush_withspecials(self):
+        s = self.start_session(fp=0.5)
+        f = self.tft()
+        s.request(f)
+        await asyncio.sleep(2)
+        assert len(s._hot_store) == 0
+        assert all([lflow.__dict__ == flow.__dict__ for lflow, flow in list(zip(s.load_view(), [f]))])
+
+        f.server_conn.via = tflow.tserver_conn()
+        s.request(f)
+        await asyncio.sleep(1)
+        assert len(s._hot_store) == 0
+        assert all([lflow.__dict__ == flow.__dict__ for lflow, flow in list(zip(s.load_view(), [f]))])
+
+        flows = [self.tft() for _ in range(500)]
+        s.update(flows)
+        fp = s._flush_period
+        fr = s._flush_rate
+        await asyncio.sleep(0.6)
+        assert s._flush_period < fp and s._flush_rate > fr
+
+    @pytest.mark.asyncio
+    async def test_bodies(self):
+        # Need to test for configure
+        # Need to test for set_order
+        s = self.start_session(fp=0.5)
+        f = self.tft()
+        f2 = self.tft(start=1)
+        f.request.content = b"A"*1001
+        s.request(f)
+        s.request(f2)
+        await asyncio.sleep(1.0)
+        content = s.db_store.con.execute(
+            "SELECT type_id, content FROM body WHERE body.flow_id == (?);", [f.id]
+        ).fetchall()[0]
+        assert content == (1, b"A"*1001)
+        assert s.db_store.body_ledger == {f.id}
+        f.response = http.HTTPResponse.wrap(tutils.tresp(content=b"A"*1001))
+        f2.response = http.HTTPResponse.wrap(tutils.tresp(content=b"A"*1001))
+        # Content length is wrong for some reason -- quick fix
+        f.response.headers['content-length'] = b"1001"
+        f2.response.headers['content-length'] = b"1001"
+        s.response(f)
+        s.response(f2)
+        await asyncio.sleep(1.0)
+        rows = s.db_store.con.execute(
+            "SELECT type_id, content FROM body WHERE body.flow_id == (?);", [f.id]
+        ).fetchall()
+        assert len(rows) == 1
+        rows = s.db_store.con.execute(
+            "SELECT type_id, content FROM body WHERE body.flow_id == (?);", [f2.id]
+        ).fetchall()
+        assert len(rows) == 1
+        assert s.db_store.body_ledger == {f.id}
+        assert all([lf.__dict__ == rf.__dict__ for lf, rf in list(zip(s.load_view(), [f, f2]))])