sequencefile

I am able to run this script to save the file in text format, but when I try to run saveAsSequenceFile it is erroring out. If any one have idea about how to save the RDD as sequence file, please let me know the process. I tried looking for solution in "Learning Spark" as well as official Spark documentation. This runs successfully dataRDD = sc.textFile("/user/cloudera/sqoop_import/departments") dataRDD.saveAsTextFile("/user/cloudera/pyspark/departments") This fails dataRDD = sc.textFile("/user/cloudera/sqoop_import/departments") dataRDD.saveAsSequenceFile("/user/cloudera/pyspark/departmentsSeq

一、SequenceFile SequenceFile的存储类似于Log文件，所不同的是Log File的每条记录的是纯文本数据，而SequenceFile的每条记录是可序列化的字符数组。 SequenceFile可通过如下API来完成新记录的添加操作: fileWriter.append(key,value) 可以看到，每条记录以键值对的方式进行组织，但前提是Key和Value需具备序列化和反序列化的功能 Hadoop预定义了一些Key Class和Value Class，他们直接或间接实现了Writable接口，满足了该功能，包括： Text 等同于Java中的String IntWritable 等同于Java中的Int BooleanWritable 等同于Java中的Boolean . . 在存储结构上，SequenceFile主要由一个Header后跟多条Record组成，如图所示： Header主要包含了Key classname，Value classname，存储压缩算法，用户自定义元数据等信息，此外，还包含了一些同步标识，用于快速定位到记录的边界。 每条Record以键值对的方式进行存储，用来表示它的字符数组可依次解析成：记录的长度、Key的长度、Key值和Value值，并且Value值的结构取决于该记录是否被压缩。 数据压缩有利于节省磁盘空间和加快网络传输

I have a bunch of Hadoop SequenceFiles that have been written with some Writable subclass I wrote. Let's call it FishWritable. This Writable worked out well for a while, until I decided there was need for a package renaming for clarity. So now the fully qualified name of FishWritable is com.vertebrates.fishes.FishWritable instead of com.mammals.fishes.FishWritable . It was a reasonable change given how the scope of the package in question had evolved. Then I discover that none of my MapReduce jobs will run, as they crash when attempting to initialize the SequenceFileRecordReader: java.lang

I have a CSV file which I would like to convert to a SequenceFile, which I would ultimately use to create NamedVectors to use in a clustering job. I've been using the seqdirectory command to try to make a SequenceFile, and then fed that output into seq2sparse with the -nv option to create NamedVectors. It seems like this is giving one big vector as an output, but I ultimately want each line of my CSV to become a NamedVector. Where am I going wrong? Julian Ortega seqdirectory command takes every file as a document, so in reality, you only have one document, hence you only get one vector. To