Support Questions
Find answers, ask questions, and share your expertise

Apache Pig load only New files using LOAD Statement

Contributor

Hi all,

I want to load only new files from the Apache Pig  LOAD statement. I have 25 files in HDFS directory and on other days I upload another few files in the same directory of HDFS. But now I just want to load only those files which are still unloaded (New files) in the Pig.

How could I achieve this?

 

Thanks,

Jay.

4 REPLIES 4

New Contributor

I also have some questions that, why upload the whole folder when changes are happening in a few files. Can anyone answer?

Contributor

Hi @pateljay .

 

A- you can use shell-script to identify newly file with current directory and load it.

 

B-or after first time pig load completion ,remove Tthat files into another directory or delete directly if not required.

C-or write python or java code that identify the timestamp for newly files and load that file with pig.

 

This link may be helpful-

https://stackoverflow.com/questions/12630584/load-multiple-files-in-pig

 

Thanks

HadoopHelp

Contributor

@HadoopHelp 

 

as I didn't yet use shell script more, could you please provide me a sample shell-script for that ??

Contributor

Hi @pateljay .

 

i am sharing dummy python code . that code is taking new file from some dir and moving to another directory .

 

 

import time
import os
import shutil

SECONDS_IN_DAY = 120 #inseconds

src="C:\\Users\Ramesh.kumar\Desktop\SourceData"
dst = "C:\\Users\Ramesh.kumar\Desktop\newDataIdentified"
Data ="C:\\Users\Ramesh.kumar\Desktop\MoveToLinux"

now = time.time()
before = now - SECONDS_IN_DAY
print("time interval is:",before)

def last_mod_time(fname):
    return os.path.getmtime(fname)

for fname in os.listdir(src):
    src_fname = os.path.join(src, fname)
    data_fname = os.path.join(Data, fname)
    if last_mod_time(src_fname) > before:
        dst_fname = os.path.join(dst, fname)
        print("-------------------------------------------------------------------------------")
        print("data is going to from A TO B")
        print("-------------------------------------------------------------------------------")
        shutil.copy(src_fname, dst_fname)
        shutil.move(dst_fname,data_fname)
        print("-------------------------------------------------------------------------------")
        print("new data has been moved")
        print("-------------------------------------------------------------------------------")



 

Note- if you are using hue or any job scheduler then you can easily achieve that.

 

Shell-script dummy -

 

echo "............................................................BANGALORE................................................................................."
echo "............................................................This is CCDA Job.........................................................................."
echo "........................................................Spark Job is going To START..................................................................."
echo "........................................................Spark is Ready to RUN........................................................................."
spark-submit python1.py
echo ".......................................................Spark job has been completed..................................................................."
echo ".......................................................Now PIG Query is going To RUN.................................................................."
pig -f ccd_cit_py.pig
echo ".......................................................PIG Query Completed here......................................................................."
echo "....................................................Now Going to create Hive Stage Table.............................................................."
echo ".....................................................Ready to create hive stage Table................................................................."
hive -f ccda_pig_hive_cit1.sql
echo "......................................................hive stage Table created........................................................................"
echo "......................................................Now Going Create Final Table...................................................................."
echo ".......................................................Ready to Create Final Table...................................................................."
hive -f ccda_pig_hive_cit_final.sql
echo "-------------------------------------------------------Final Table has been Created-------------------------------------------------------------------"
echo "--------------------------------------------------------demography table id going to create here-------------------------------------------------------"
hive -f DemoGrapghy.sql
echo "---------------------------------------------------------demoGraphy Table has been Created------------------------------------------------------------"
echo "-------------------------------------------------------HRK_CCDFile Table is going to create-----------------------------------------------------------"
echo "-----------------------------------------------------HRK_CCDFile Table has been Created---------------------------------------------------------------"
echo "......................................................ALL Table is created on Hive.................................................................."
echo "..................................................Now Going To Delete PIG INPUTPATH from HDFS........................................................."
echo "......................................................Ready To Delete PIG INPUTPATH..................................................................."
hdfs dfs -rmr /user/root/BigDataTest/CCDACIT/CCDAPYOUTPUTDATA/A
echo ".......................................................PIG INPUTPATH Deleted.........................................................................."
echo "......................................................................................................................................................"
echo "....................................................Now Going to Delete PIG OUTPUTPATH from HDFS......................................................"
echo "........................................................Ready To Delete PIG OUTPUTPATH................................................................"
echo ".............................................................................................................................................."
echo "............................................................BANGALORE................................................................................."
echo "............................................................This is CCDA Job.........................................................................."
echo "........................................................Spark Job is going To START..................................................................."
echo "........................................................Spark is Ready to RUN........................................................................."
spark-submit python1.py
echo ".......................................................Spark job has been completed..................................................................."
echo ".......................................................Now PIG Query is going To RUN.................................................................."
pig -f ccd_cit_py.pig
echo ".......................................................PIG Query Completed here......................................................................."

 

Note - you need to add script as per your requirements .

reference link-

https://unix.stackexchange.com/questions/24952/script-to-monitor-folder-for-new-files

 

 

Thanks

HadoopHelp