使用 Python 连接到 Redshift 数据 - 错误：当前事务被中止，命令被忽略，直到事务块结束

Question

I am trying to connect the Redshift data using Python (Jupyter Notebook). after running the last line, am getting this error:

InFailedSqlTransaction: current transaction is aborted, commands ignored until end of transaction block

could you please help me here.

import psycopg2
con=psycopg2.connect(dbname= 'TBD', host='TBD', 
port= 'TBD', user= 'TBD', password= 'TBD')
cur = con.cursor()
cur.execute("SELECT site_id FROM dfa_std")

Answer 1

As well as psycopg2 you need have sqlalchemy and ipython-sql installed in the Notebook server's Python.

Create a file with your Redshift endpoint and credentials:

echo "{
  \"user_name\": \"my_user\",
  \"password\": \"my_pswd\",
  \"host_name\": \"my_cluster_endpoint\",
  \"port_num\": \"5439\",
  \"db_name\": \"my_db\"
}" > my.creds

Then try this in your notebook:

import sqlalchemy
import psycopg2
import simplejson

%reload_ext sql
%config SqlMagic.displaylimit = 25

with open("my.creds") as fh:
    creds = simplejson.loads(fh.read())
connect_to_db = "postgresql+psycopg2://" + \
                creds["user_name"] +':'+ creds["password"] +'@'+ \
                creds["host_name"] +':'+ creds["port_num"] +'/'+ creds["db_name"];
%sql $connect_to_db
%sql SELECT current_user, version();

Expected output:

'Connected: my_user@my_db'

current_user | version
 my_user     | PostgreSQL 8.0.2 on i686-pc-linux-gnu, compiled by GCC gcc (GCC) 3.4.2 20041017 (Red Hat 3.4.2-6.fc3), Redshift 1.0.24238