我能够使用pandas和psycopg2连接到远程PostgreSQL服务器。现在,由于知道熊猫读取数据库的速度很慢,我认为使用Dask可以解决此问题。因此,我决定与Psycopg2和Dask一起运行,但收到以下错误:
import psycopg2 as pg
from sqlalchemy import create_engine
import dask.dataframe as dd
import pandas.io.sql as psql
import pandas as pd
connection = pg.connect("host='xxx.x.x.x' dbname=xxxx user=xxxx password='xxxx' port = 'xxxx'")
df = dd.read_sql_table(table='xxxx',uri='postgresql+psycopg2://user_name:password@localhost:port_number/database_name',index_col='id',npartitions=20)
df.compute()
c:\users\user_name\miniconda3\lib\site-packages\sqlalchemy\dialects\postgresql\base.py:3323: SAWarning: Skipped unsupported reflection of expression-based index uc_table_name_lower_code
"expression-based index %s" % idx_name
上述错误是什么意思?即使出现错误,它也会显示表数据框。 如何在没有收到错误消息的情况下运行连接?