Why are you using Sequence files? Sequence files are binary key/value stores, I haven't used them but it sounds from the docs that each 'value' is a record, so one type sounds correct. You might consider trying Textfile or ORC? You might get better results.
/Greg On Thu, Mar 22, 2018 at 10:06 AM, Raymond Xie <[email protected]> wrote: > I have a sequence file generated using sqoop, why only one type is seen in > the file? > > sqoop import -m 1 \ > --connect=jdbc:mysql://ms.itversity.com/retail_db \ > --username=retail_user \ > --password=itversity \ > --table=orders \ > --as-sequencefile \ > --target-dir=order20180320_seq > > The head part of the sequence is as below: > > [paslechoix@gw03 ~]$ hdfs dfs -cat order20180320_seq/part-m-00000 |head > SEQ!org.apache.hadoop.io.LongWritableorders7▒▒P▒ > U3▒3▒$@▒▒-OCLOSED@▒▒PENDING_PAYMENT@▒▒/COMPLETE@▒▒"{CLOSED@▒▒ > ,COMPLETE@▒COMPLETE@▒▒COMPLET@▒▒ > > As you can see, there is only one type in the sequence file's head: > LongWritable. > > According to this Hadoop WiKi about sequence file format: > https://wiki.apache.org/hadoop/SequenceFile > > sequence file's header should contain: > > version - A byte array: 3 bytes of magic header 'SEQ', followed by 1 byte of > actual version no. (e.g. SEQ4 or SEQ6) > keyClassName - String > valueClassName - String > > However, all the sequence files I generated with sqoop (1.4.6.2.5.0.0-1245 > ) contains only one Class. > > Is there anything missing in the sqoop command? how can generate a > sequence with the right info in its head? > > Thank you very much. > > > *------------------------------------------------* > *Sincerely yours,* > > > *Raymond* >
