WebMay 14, 2024 · 一般有三种方法:计数 ( RDD.count ),分区 ( RDD.partitions.length ),计数+分区 ( RDD.isEmpty )。 RDD.count 适用于所有类型的DStream,但由于是Action算子,会触发SparkContext.runJob方法,从而导致Job的提交和运行,当数据量较大时,代价也比较大。 不推荐。 RDD.partitions.length 通过RDD的分区数来判断,但不适用 … WebisEmpty () 获取RDD是否为空,如果RDD为Nothing或Null,则抛出异常 /** * @note due to complications in the internal implementation, this method will raise an * exception if called on an RDD of `Nothing` or `Null`. This may be come up in practice * because, for example, the type of `parallelize (Seq ())` is `RDD [Nothing]`.
Scala 如何使用Spark计算累积和_Scala_Apache Spark - 多多扣
Webtf = isEmpty(obj) returns a logical 1 (true) if the input RDD obj contains no elements, and a logical 0 (false) otherwise. Input Arguments. expand all. ... tf — Input RDD is empty or not … Webimport org.apache.spark.SparkConf: import org.apache.spark.mllib.classification.{LogisticRegressionWithLBFGS, NaiveBayes} import org.apache.spark.mllib.linalg.Vectors grace cleaning maintenance
关于性能:如何有效检查RDD是否为空? 码农家园
WebSpark的RDD编程03 9.2.1.5 join练习 以后在计算的过程中我们不可能是单文件计算,以后会涉及到多个文件联合计算 现在存在这样的两个文件 # 需求 # 存在这样一个表 movies电影表 # movie_id movie_name mov WebAug 24, 2024 · dataframe.rdd.isEmpty () : This approach converts the dataframe to rdd which may not utilize the underlying optimizer (catalyst optimizer) and slows down the … WebInstead, use better performant function, such as df.schema () or df.rdd.isEmpty (). Test the AWS Glue job on a development endpoint and optimize the ETL code accordingly. If none of the preceding solution options work, split the input data into chunks or partitions. Then, run multiple AWS Glue ETL jobs instead of running one big job. grace clinic hamilton center