diff --git a/scripts/synapse_port_db b/scripts/synapse_port_db
index d46581e4e..7b23a4485 100755
--- a/scripts/synapse_port_db
+++ b/scripts/synapse_port_db
@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 # Copyright 2015, 2016 OpenMarket Ltd
+# Copyright 2018 New Vector Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -250,6 +251,12 @@ class Porter(object):
     @defer.inlineCallbacks
     def handle_table(self, table, postgres_size, table_size, forward_chunk,
                      backward_chunk):
+        logger.info(
+            "Table %s: %i/%i (rows %i-%i) already ported",
+            table, postgres_size, table_size,
+            backward_chunk+1, forward_chunk-1,
+        )
+
         if not table_size:
             return
 
@@ -467,31 +474,10 @@ class Porter(object):
             self.progress.set_state("Preparing PostgreSQL")
             self.setup_db(postgres_config, postgres_engine)
 
-            # Step 2. Get tables.
-            self.progress.set_state("Fetching tables")
-            sqlite_tables = yield self.sqlite_store._simple_select_onecol(
-                table="sqlite_master",
-                keyvalues={
-                    "type": "table",
-                },
-                retcol="name",
-            )
-
-            postgres_tables = yield self.postgres_store._simple_select_onecol(
-                table="information_schema.tables",
-                keyvalues={},
-                retcol="distinct table_name",
-            )
-
-            tables = set(sqlite_tables) & set(postgres_tables)
-
-            self.progress.set_state("Creating tables")
-
-            logger.info("Found %d tables", len(tables))
-
+            self.progress.set_state("Creating port tables")
             def create_port_table(txn):
                 txn.execute(
-                    "CREATE TABLE port_from_sqlite3 ("
+                    "CREATE TABLE IF NOT EXISTS port_from_sqlite3 ("
                     " table_name varchar(100) NOT NULL UNIQUE,"
                     " forward_rowid bigint NOT NULL,"
                     " backward_rowid bigint NOT NULL"
@@ -517,18 +503,33 @@ class Porter(object):
                     "alter_table", alter_table
                 )
             except Exception as e:
-                logger.info("Failed to create port table: %s", e)
+                pass
 
-            try:
-                yield self.postgres_store.runInteraction(
-                    "create_port_table", create_port_table
-                )
-            except Exception as e:
-                logger.info("Failed to create port table: %s", e)
+            yield self.postgres_store.runInteraction(
+                "create_port_table", create_port_table
+            )
 
-            self.progress.set_state("Setting up")
+            # Step 2. Get tables.
+            self.progress.set_state("Fetching tables")
+            sqlite_tables = yield self.sqlite_store._simple_select_onecol(
+                table="sqlite_master",
+                keyvalues={
+                    "type": "table",
+                },
+                retcol="name",
+            )
 
-            # Set up tables.
+            postgres_tables = yield self.postgres_store._simple_select_onecol(
+                table="information_schema.tables",
+                keyvalues={},
+                retcol="distinct table_name",
+            )
+
+            tables = set(sqlite_tables) & set(postgres_tables)
+            logger.info("Found %d tables", len(tables))
+
+            # Step 3. Figure out what still needs copying
+            self.progress.set_state("Checking on port progress")
             setup_res = yield defer.gatherResults(
                 [
                     self.setup_table(table)
@@ -539,7 +540,8 @@ class Porter(object):
                 consumeErrors=True,
             )
 
-            # Process tables.
+            # Step 4. Do the copying.
+            self.progress.set_state("Copying to postgres")
             yield defer.gatherResults(
                 [
                     self.handle_table(*res)
@@ -548,6 +550,9 @@ class Porter(object):
                 consumeErrors=True,
             )
 
+            # Step 5. Do final post-processing
+            yield self._setup_state_group_id_seq()
+
             self.progress.done()
         except:
             global end_error_exec_info
@@ -707,6 +712,16 @@ class Porter(object):
 
         defer.returnValue((done, remaining + done))
 
+    def _setup_state_group_id_seq(self):
+        def r(txn):
+            txn.execute("SELECT MAX(id) FROM state_groups")
+            next_id = txn.fetchone()[0]+1
+            txn.execute(
+                "ALTER SEQUENCE state_group_id_seq RESTART WITH %s",
+                (next_id,),
+            )
+        return self.postgres_store.runInteraction("setup_state_group_id_seq", r)
+
 
 ##############################################
 ###### The following is simply UI stuff ######