通过Pyspark查询Hive返回空结果

Question

我在AWS EMR集群上运行spark 2.1.0（基于以下内容 - https://aws.amazon.com/blogs/big-data/running-jupyter-notebook-and-jupyterhub-on-amazon-emr/）

我尝试查询存在的表并在远程HIVE中包含数据。 Spark正确地干扰了架构，但表内容为空。有什么想法吗？

import os
import findspark
findspark.init('/usr/lib/spark/')

# Spark related imports
from pyspark.sql import SparkSession
from pyspark import SparkContext

sc = SparkContext.getOrCreate()
spark = SparkSession.builder.config(conf=sc.getConf()).getOrCreate()

remote_hive = "jdbc:hive2://myhost:10000/mydb"
driver = "org.apache.hive.jdbc.HiveDriver"
user="user"
password = "password"

df = spark.read.format("jdbc").\
    options(url=remote_hive, 
            driver=driver, 
            user=user, 
            password=password, 
            dbtable="mytable").load()


df.printSchema()
# returns the right schema
df.count()
0

Answer 1

你可以尝试 -

spark\
  .read.format("jdbc")\
  .option("driver", driver)
  .option("url", remote_url)
  .option("dbtable", "mytable")
  .option("user", "user")\
  .option("password", "password")
  .load()