在Apache Spark中,分区parquet的惰性加载可以通过以下步骤来实现:
import org.apache.spark.SparkConf
import org.apache.spark.sql.{DataFrame, SparkSession}
val conf = new SparkConf().setAppName("Lazy Loading Partitioned Parquet")
val spark = SparkSession.builder().config(conf).getOrCreate()
val parquetPath = "path_to_parquet_file"
val parquetDF: DataFrame = spark.read.parquet(parquetPath)
parquetDF.createOrReplaceTempView("parquetTable")
val resultDF = spark.sql("SELECT * FROM parquetTable WHERE partition_column = 'value'")
完整的代码示例如下所示:
import org.apache.spark.SparkConf
import org.apache.spark.sql.{DataFrame, SparkSession}
object LazyLoadingPartitionedParquet {
def main(args: Array[String]): Unit = {
val conf = new SparkConf().setAppName("Lazy Loading Partitioned Parquet")
val spark = SparkSession.builder().config(conf).getOrCreate()
val parquetPath = "path_to_parquet_file"
val parquetDF: DataFrame = spark.read.parquet(parquetPath)
parquetDF.createOrReplaceTempView("parquetTable")
val resultDF = spark.sql("SELECT * FROM parquetTable WHERE partition_column = 'value'")
resultDF.show()
}
}
请替换path_to_parquet_file
和partition_column
为实际的路径和分区列名称。