diff --git a/swh/cloner/git/storage/db.py b/swh/cloner/git/storage/db.py
index c933d55..378090c 100644
--- a/swh/cloner/git/storage/db.py
+++ b/swh/cloner/git/storage/db.py
@@ -1,77 +1,63 @@
 # Copyright (C) 2015  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import psycopg2
 
 
 def connect(db_url):
     """Open db connection.
     """
     return psycopg2.connect(db_url)
 
 
-def execute(cur, query_params, trace=None):
+def entry_to_bytes(entry):
+    """Convert an entry coming from the database to bytes"""
+    if isinstance(entry, memoryview):
+        return entry.tobytes()
+    return entry
+
+
+def line_to_bytes(line):
+    """Convert a line coming from the database to bytes"""
+    return line.__class__(entry_to_bytes(entry) for entry in line)
+
+
+def cursor_to_bytes(cursor):
+    """Yield all the data from a cursor as bytes"""
+    yield from (line_to_bytes(line) for line in cursor)
+
+
+def execute(cur, query_params):
     """Execute the query_params.
     query_params is expected to be either:
     - a sql query (string)
     - a tuple (sql query, params)
     """
     if isinstance(query_params, str):
         cur.execute(query_params)
     else:
-        if trace is not None:
-            print("mogrify: ", cur.mogrify(*query_params).decode())
         cur.execute(*query_params)
 
 
-def copy_from(cur, file, table):
-    """Copy the content of a file to the db in the table table.
-    """
-    cur.copy_from(file, table)
-
-
 def query_execute(db_conn, query_params):
     """Execute one query.
     Type of sql queries: insert, delete, drop, create...
     query_params is expected to be either:
     - a sql query (string)
     - a tuple (sql query, params)
     """
     with db_conn.cursor() as cur:
         execute(cur, query_params)
 
 
-def queries_execute(db_conn, queries_params, trace=None):
-    """Execute multiple queries without any result expected.
-    Type of sql queries: insert, delete, drop, create...
-    query_params is expected to be a list of mixed:
-    - sql query (string)
-    - tuple (sql query, params)
-    """
-    with db_conn.cursor() as cur:
-        for query_params in queries_params:
-            execute(cur, query_params, trace)
-
-
-def query_fetchone(db_conn, query_params):
-    """Execute sql query which returns one result.
-    query_params is expected to be either:
-    - a sql query (string)
-    - a tuple (sql query, params)
-    """
-    with db_conn.cursor() as cur:
-        execute(cur, query_params)
-        return cur.fetchone()
-
-
-def query_fetch(db_conn, query_params, trace=None):
+def query_fetch(db_conn, query_params):
     """Execute sql query which returns results.
     query_params is expected to be either:
     - a sql query (string)
     - a tuple (sql query, params)
     """
     with db_conn.cursor() as cur:
-        execute(cur, query_params, trace)
-        return cur.fetchall()
+        execute(cur, query_params)
+        yield from cursor_to_bytes(cur)
diff --git a/swh/cloner/git/storage/models.py b/swh/cloner/git/storage/models.py
index e30cffa..128df53 100644
--- a/swh/cloner/git/storage/models.py
+++ b/swh/cloner/git/storage/models.py
@@ -1,62 +1,33 @@
 # Copyright (C) 2015  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 from swh.cloner.git.storage import db
 
 
-def load_repos(db_conn, limit=10):
+def load_repos(db_conn):
     """List the repository.
     Limit the number of repository to load.
-    10 is the default if no limit is provided.
-    NOT USED YET?!
     """
-    return db.query_fetch(db_conn, ("""SELECT id, full_name
-                                       FROM orig_repos
-                                       LIMIT %s""",
-                                    (limit,)))
-
-
-def load_random_1_percent_repos(db_conn):
-    """Load the 1 percent repositories at random.
-    NOT USED YET?!
-    """
-    return db.query_fetch(db_conn, """SELECT id, full_name
-                                      FROM repos_random_sample(1)
-                                      UNION ALL
-                                      SELECT id, full_name, html_url
-                                      FROM repos_well_known();""")
-
-
-def load_random_sample(db_conn, table='sample', limit=None, offset=None):
-    """Load the table sample containing random sample of repositories to fetch.
-    """
-    if limit:
-        query_limit = ' order by id limit ' + limit
-        query_limit += '' if not offset else ' offset ' + offset
-    else:
-        query_limit = ''
-
-    query = 'SELECT id, full_name FROM ' + table + query_limit
-    return db.query_fetch(db_conn, query)
+    yield from db.query_fetch(db_conn, 'select id, full_name from missing_orig_repos order by id')
 
 
 def persist_task_result(db_conn, repo_id, task_id, task_start_date,
                         task_duration, status, json_result, stdout, stderr):
     """Persist the task's result.
     """
     return db.query_execute(db_conn, ("""INSERT INTO crawl_history
                                         (repo, task_id, date, duration, status,
                                          result, stdout, stderr)
                                         VALUES(%s, %s, %s, %s, %s,
                                                %s, %s, %s)
                                      """,
                                       (repo_id,
                                        task_id,
                                        task_start_date,
                                        task_duration,
                                        status,
                                        json_result,
                                        stdout,
                                        stderr)))