日志分析的Apache猪

Question

我有此行的日志：

in24.inetnebr.com - - [01/Aug/1995:00:00:01 -0400] "GET /shuttle/missions/sts-68/news/sts-68-mcc-05.txt HTTP/1.0" 200 1839 

其中第一列（in24.inetnebr.com）是主机，所述第二（01/Aug/1995:00:00:01 -0400）是时间戳，所述第三（GET /shuttle/missions/sts-68/news/sts-68-mcc-05.txt HTTP/1.0）是下载页。

我如何才能找到Pig的每个主机的最后两个下载页面？

非常感谢您的帮助！

Answer 1

我已经解决了这个问题，供参考：

REGISTER piggybank.jar 
DEFINE SUBSTRING org.apache.pig.piggybank.evaluation.string.SUBSTRING(); 

raw = LOAD 'nasa' USING org.apache.hcatalog.pig.HCatLoader(); --cast the data, to make possible the usage of string functions 

rawCasted = FOREACH raw GENERATE (chararray)host as host, (chararray)xdate as xdate,(chararray)address as address; --cut out the date, and put together the used columns 

rawParsed = FOREACH rawCasted GENERATE host, SUBSTRING(xdate,1,20) as xdate, address; --make sure that the not full columns are omitted 

rawFiltered = FILTER rawParsed BY xdate IS NOT NULL; --cast the timestamp to timestamp format 

analysisTable = FOREACH rawFiltered GENERATE host, ToDate(xdate, 'dd/MMM/yyyy:HH:mm:ss') as xdate, address; 

aTgrouped = GROUP analysisTable BY host; 

resultsB = FOREACH aTgrouped { 
elems=ORDER analysisTable BY xdate DESC; 
two=LIMIT elems 2; --Choose the last two page 

fstB=ORDER two BY xdate DESC; 
fst=LIMIT fstB 1; --Choose the last page 

sndB=ORDER two BY xdate ASC; 
snd=LIMIT sndB 1; --Choose the previous page 

GENERATE FLATTEN(group), fst.address, snd.address; --Put together the pages 
}; 
DUMP resultsB;