Read SQL query from psycopg2 into pandas dataframe

connect_psycopg2_to_pandas.py

import pandas as pd
import pandas.io.sql as sqlio
import psycopg2

conn = psycopg2.connect("host='{}' port={} dbname='{}' user={} password={}".format(host, port, dbname, username, pwd))
sql = "select count(*) from table;"
dat = sqlio.read_sql_query(sql, conn)
conn = None

does anyone now if pd.read_sql blocks? im have a multi-thread process that uses it, and it seems to block