psycopg2 (insert, update) writing problem

It is most likely a lock in the database, with thread/processes trying to update the same record.

import psycopg2

conn = psycopg2.connect(
       database="dbasename",user="username",
       password='your_password',host='web_address',
       port='your_port')
cursor = conn.cursor()
cursor.execute(
  "UPDATE table_name SET update_column_name=(%s)"
  " WHERE ref_column_id_value = (%s)", 
  ("column_name","value_you_want_to_update",));
conn.commit()
cursor.close()

You did not format your execute statement correctly.