returns null. if partNum is out of range of split parts, returns empty string. If partNum is 0, throws an error. If partNum is negative, the parts are counted backward from the end of the string. If the delimiter is an empty
第一种方法split(String regex, int limit) 官方解释: Splits this string around matches of the given regular expression. //根据给定的正则表达式来分解这个String The array returned by this method contains each substring of this string that is terminated by another substring that matches the given expr...
map(_.split(",")) .map(attributes => Row(attributes(0), attributes(1).trim)) // 将模式应用于RDD val peopleDF = spark.createDataFrame(rowRDD, schema) // 使用DataFrame创建一个临时视图 peopleDF.createOrReplaceTempView("people") // 可以通过使用DataFrames提供的SQL方法运行SQL语句 val results...
String selectSql ="INSERT OVERWRITE TABLE table PARTITION(dt='${dt}') SELECT /*+ REPARTITION(10) */ * FROM ( SELECT /*+ BROADCAST(b) */ * FROM ( SELECT * FROM data WHERE dt='${dt}' ) a inner JOIN ( SELECT * FROM con_tabl1 ) UNION ALL ( SELECT * FROM con_tabl2) UNION...
conf spark.driver.resourceSpec=small;conf spark.executor.instances=1;conf spark.executor.resourceSpec=small;conf spark.app.name=Spark SQL Test;conf spark.adb.connectors=oss;use tpcd;select * from customer order by C_CUSTKEY desc limit 100;根据前面的公式计算 defaultMaxSplitBytes = 128MBopen...
使用Spark計算引擎訪問Table Store時,您可以通過E-MapReduce SQL或者DataFrame編程方式對錶格儲存中資料進行複雜的計算和高效的分析。 功能特性 對於批次計算,除了基礎功能外,Tablestore On Spark提供了如下核心最佳化功能: 索引選擇:資料查詢效率的關鍵在於選擇合適的索引方式,根據過濾條件選擇最匹配的索引方式增加查詢效率...
// 文件是否可split,parquet/orc/avro均可被split val isSplitable = relation.fileFormat.isSplitable( relation.sparkSession, relation.options, filePath) // 切分文件 PartitionedFileUtil.splitFiles( sparkSession = relation.sparkSession, file = file, ...
import org.apache.spark.sql.Encoder import spark.implicits._ object RDDtoDF { def main(args: Array[String]) { case class Employee(id:Long,name: String, age: Long) val employeeDF = spark.sparkContext.textFile("file:///usr/local/spark/employee.txt").map(_.split(",")).map(attributes...
首先spark.sql.files.openCostInBytes 该参数配置的值和bytesPerCore 取最大值// 然后,比较spark.sql.files.maxPartitionBytes 取小者val maxSplitBytes=Math.min(defaultMaxSplitBytes,Math.max(openCostInBytes,bytesPerCore))logInfo(s"Planning scan with bin packing, max size: $maxSplitBytes bytes, "+s"...
// 文件是否可split,parquet/orc/avro均可被split val isSplitable = relation.fileFormat.isSplitable( relation.sparkSession, relation.options, filePath) // 切分文件 PartitionedFileUtil.splitFiles( sparkSession = relation.sparkSession, file = file, ...