1、描述spark中怎么加载lzo压缩格式的文件
2、比较lzo格式文件以textFile方式和LzoTextInputFormat方式计算数据,Running Tasks个数的影响
a.确保lzo文件所在文件夹中生成lzo.index索引文件
b.以LzoTextInputFormat处理,能够正常按分块数分配Tasks
查看文件块数量
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[tech@dx2 ~]$ hdfs fsck /wh/source/hotel .2017-08-07.txt_10.10.16.105_20170807.lzo
Connecting to namenode via http: //nn1 .zdp.ol:50070
FSCK started by bwtech (auth:SIMPLE) from /10 .10.16.103 for path /wh/source/hotel .2017-08-07.txt_10.10.16.105_20170807.lzo at Tue Aug 08 15:27:52 CST 2017
.Status: HEALTHY Total size:2892666412 B
Total dirs :0
Total files:1
Total symlinks:0
Total blocks (validated):11 (avg. block size 262969673 B)
Minimally replicated blocks:11 (100.0 %)
Over-replicated blocks:0 (0.0 %)
Under-replicated blocks:0 (0.0 %)
Mis-replicated blocks:0 (0.0 %)
Default replication factor:3
Average block replication:3.0
Corrupt blocks:0
Missing replicas:0 (0.0 %)
Number of data-nodes:21
Number of racks:2
FSCK ended at Tue Aug 08 15:27:52 CST 2017 in 3 milliseconds
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Spark源代码可以参考https://github.com/chocolateBlack/LearningSpark/blob/master/src/main/scala-2.11/SparkLzoFile.scala
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import com.hadoop.mapreduce.LzoTextInputFormat
import org.apache.hadoop.io.{Text, LongWritable}
import org.apache.spark.{SparkContext, SparkConf}
object SparkLzoFile{
def main(args : Array[String]){
val conf = new SparkConf().setAppName( "Spark_Lzo_File" )
val sc = new SparkContext(conf)
//文件路径
val filePath = "/wh/source/hotel.2017-08-07.txt_10.10.16.105_20170807.lzo"
//按textFile方式加载文件
val textFile = sc.textFile(filePath)
//按lzoTextInputFormat加载数据文件
val lzoFile = sc.newAPIHadoopFile[LongWritable, Text, LzoTextInputFormat](filePath)
println(textFile.partitions.length) // partitions个数输出 1
println(lzoFile.partitions.length) // partitions个数输出 11
//两种方式计算word count查看后台任务
lzoFile.map( _ . _ 2 .toString).flatMap(x = >x.split( "-" )).map(( _ , 1 )).reduceByKey( _ + _ ).collect
textFile.flatMap(x = >x.split( "\t" )).map(( _ , 1 )).reduceByKey( _ + _ ).collect
}
} |