python - 如何在 PySpark 中连接到 Presto JDBC？

Question

我想在 PySpark 中使用 JDBC 连接到 Presto 服务器。我关注了tutorial这是用Java编写的。我试图在我的 Python3 代码中执行相同的操作，但出现错误:

:java.sql.SQLException:没有合适的驱动程序

我尝试执行以下代码:

jdbcDF = spark.read \
    .format("jdbc") \
    .option("url", "jdbc:presto://my_machine_ip:8080/hive/default") \
    .option("user", "airflow") \
    .option("dbtable", "may30_1") \
    .load()

需要注意的是，我在 EMR 上使用 Spark，因此已经向我提供了 spark。

上述教程中的代码是:

final String JDBC_DRIVER = "com.facebook.presto.jdbc.PrestoDriver";
    final String DB_URL = "jdbc:presto://localhost:9000/catalogName/schemaName";
    //  Database credentials
    final String USER = "username";
    final String PASS = "password";
    Connection conn = null;
    Statement stmt = null;
    try {
      //Register JDBC driver
      Class.forName(JDBC_DRIVER);

请注意上面代码中的JDBC_DRIVER，我无法在Python3中推导出相应的赋值即在PySpark中。

我也没有在任何配置中添加任何依赖项。

我希望能够成功连接到我的 presto。现在，我收到以下错误，完整的堆栈跟踪:

Traceback (most recent call last):
  File "<stdin>", line 5, in <module>
  File "/usr/lib/spark/python/pyspark/sql/readwriter.py", line 172, in load
    return self._df(self._jreader.load())
  File "/usr/lib/spark/python/lib/py4j-0.10.7-src.zip/py4j/java_gateway.py", line 1257, in __call__
  File "/usr/lib/spark/python/pyspark/sql/utils.py", line 63, in deco
    return f(*a, **kw)
  File "/usr/lib/spark/python/lib/py4j-0.10.7-src.zip/py4j/protocol.py", line 328, in get_return_value
py4j.protocol.Py4JJavaError: An error occurred while calling o90.load.
: java.sql.SQLException: No suitable driver
    at java.sql.DriverManager.getDriver(DriverManager.java:315)
    at org.apache.spark.sql.execution.datasources.jdbc.JDBCOptions$$anonfun$6.apply(JDBCOptions.scala:105)
    at org.apache.spark.sql.execution.datasources.jdbc.JDBCOptions$$anonfun$6.apply(JDBCOptions.scala:105)
    at scala.Option.getOrElse(Option.scala:121)
    at org.apache.spark.sql.execution.datasources.jdbc.JDBCOptions.<init>(JDBCOptions.scala:104)
    at org.apache.spark.sql.execution.datasources.jdbc.JDBCOptions.<init>(JDBCOptions.scala:35)
    at org.apache.spark.sql.execution.datasources.jdbc.JdbcRelationProvider.createRelation(JdbcRelationProvider.scala:32)
    at org.apache.spark.sql.execution.datasources.DataSource.resolveRelation(DataSource.scala:318)
    at org.apache.spark.sql.DataFrameReader.loadV1Source(DataFrameReader.scala:223)
    at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:211)
    at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:167)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:244)
    at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357)
    at py4j.Gateway.invoke(Gateway.java:282)
    at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132)
    at py4j.commands.CallCommand.execute(CallCommand.java:79)
    at py4j.GatewayConnection.run(GatewayConnection.java:238)
    at java.lang.Thread.run(Thread.java:748)

Answer 1

您需要执行以下步骤将 presto 连接到 pyspark。

1. 下载 Presto JDBC driver jar来自official website并放入spark master节点。

2. 使用以下参数启动 pyspark shell:

bin/pyspark --driver-class-path com.facebook.presto.jdbc.PrestoDriver --jars /path/to/presto/jdbc/driver/jar/file

尝试使用 Spark 连接到 presto

jdbcDF = spark.read \
    .format("jdbc") \
    .option("driver", "com.facebook.presto.jdbc.PrestoDriver") \  <-- presto driver class
    .option("url", "jdbc:presto://<machine_ip>:8080/hive/default") \
    .option("user", "airflow") \
    .option("dbtable", "may30_1") \
    .load()