Get the dataset from https://www.csie.ntu.edu.tw/~cjlin/libsvmtools/datasets/binary.html#webspam

Putting data on HDFS

hadoop fs -mkdir -p /dataset/webspam/raw

awk -f conv.awk webspam_wc_normalized_trigram.svm | \
hadoop fs -put - /dataset/webspam/raw/

Table preparation

create database webspam;
use webspam;

create external table webspam_raw (
  rowid int,
  label int,
  features ARRAY<STRING>
) ROW FORMAT 
DELIMITED FIELDS TERMINATED BY '\t' 
COLLECTION ITEMS TERMINATED BY "," 
STORED AS TEXTFILE LOCATION '/dataset/webspam/raw';

set hive.sample.seednumber=43;
create table webspam_test
as
select * from webspam_raw TABLESAMPLE(1000 ROWS) s
CLUSTER BY rand(43)
limit 70000;

Make auxiliary tables

create table webspam_train_orcfile (
 rowid int,
 label int,
 features array<string>
) STORED AS orc tblproperties ("orc.compress"="SNAPPY");

-- SET mapred.reduce.tasks=128;
INSERT OVERWRITE TABLE webspam_train_orcfile
select
  s.rowid, 
  label,
  add_bias(features) as features
from webspam_raw s
where not exists (select rowid from webspam_test t where s.rowid = t.rowid)
CLUSTER BY rand(43);
-- SET mapred.reduce.tasks=-1;

set hivevar:xtimes=3;
set hivevar:shufflebuffersize=100;
set hivemall.amplify.seed=32;
create or replace view webspam_train_x3
as
select
   rand_amplify(${xtimes}, ${shufflebuffersize}, *) as (rowid, label, features)
from  
   webspam_train_orcfile;

create table webspam_test_exploded as
select 
  rowid,
  label,
  split(feature,":")[0] as feature,
  cast(split(feature,":")[1] as float) as value
from 
  webspam_test LATERAL VIEW explode(add_bias(features)) t AS feature;

Caution: For this dataset, use small shufflebuffersize because each training example has lots of features though (xtimes shufflebuffersize N) training examples are cached in memory.