pyspark 从postgresql读取数据

因为我安装的是spark 3.5.6，所以需要安装

pip install pyspark==3.5.6

Pyspark从postgresql读数据

import time
from pyspark.sql import DataFrame, SparkSession,DataFrameReader
from pyspark.sql.functions import to_json, struct

spark: SparkSession.Builder = SparkSession.builder

session: SparkSession = spark.appName("Python Spark SQL data source example") \
        .config("spark.jars", r"C:\Users\84977\Downloads\postgresql-42.7.6.jar") \
        .master("spark://192.168.220.132:7077")\
        .getOrCreate()
        
last_max_id = 0  # 保存上次读取的最大ID

page_size= 2

while True:
    query = f"""
        (SELECT * FROM public.complexjson
         WHERE id > {last_max_id}
         ORDER BY id ASC
         LIMIT {page_size}) as t
    """

    df: DataFrame = session.read \
        .format("jdbc") \
        .option("url", "jdbc:postgresql://192.168.220.130:32222/postgresdb") \
        .option("dbtable", query) \
        .option("driver", "org.postgresql.Driver") \
        .option("user", "postgresadmin") \
        .option("password", "admin123") \
        .load()

    if df.count() > 0:
        df.show(truncate=False)

        json_df = df.select(to_json(struct("*")).alias("json"))
        for row in json_df.collect():
            print(row["json"])

        # 更新 last_max_id
        max_id = df.agg({"id": "max"}).collect()[0][0]
        last_max_id = max_id

    time.sleep(10)  # 每10秒轮询一次