CSGY6513 Homework 1-MapReduce  Solved

In this assignment, you will explore New York City taxi data using MapReduce and Hadoop Streaming. You will write map and reduce python programs the tasks outlined below.


Suggestion: first, run your programs on Peel using a sample (smaller) dataset to test and debug your code (you can use the lab2 data, which can be found under the /user/CS-GY-6513/lab2-data directory), and then use the large dataset to generate the results for your submission.


Data
The data (fare_data_week1.csv, trip_data_week1.csv) can be found in HDFS under the /user/CS-GY-6513/hw1.  

The directory includes a subdirectory called samples which contains two small datasets for you to test your code. Use the following command to copy the small datasets to your Peel account:

 

hfs -get /user/CS-GY-6513/hw1/samples 

 

Hint: 

Parsing can be challenging with big data. We need to be particularly careful with special characters since they can cause your scripts to crash, and when this happens, your Hadoop job simply dies. To avoid such crashes, you can add a try-except block in your code to skip these characters.

 

Submission Instructions
You will submit the map and reduce programs for all tasks in a single .zip file with the following structure:

1.    One directory per task, named taskX, where X is the task’s number. 

2.    If a task has a sub-task, use taskX-Y, where Y identifies the sub-task. 

E.g.: "task2-a" refers to sub-task "a" of Task 2. If you do an “ls” on your homework directory, it should contain the following sub-directories: task1 task2-a task2-b task2-c task2-d 

task2-e task2-f 

task3 (for extra credit) 

 

Each task directory should include a “map.py” file and a “reduce.py” file.   

Note:

-       Files names must not have spaces, commas, or special characters.

-       You should not include any input files or output files in your submission.  


You may use combiners and partitioners, but they will not be tested, i.e., your program should work correctly without combiners or partitioners.

 

You should use 2 reducers for all tasks.

 

The code for your mappers (map.py) can access the mapreduce_map_input_file environment variable to determine which input (.csv) file is being read. The CSV filenames will contain the substrings "trip" and "fare". You cannot use any other environment variables besides mapreduce_map_input_file.

 

Tester
We provide a tester that you can use to make sure that your submission has the proper structure and that your code outputs have the correct format and that . The tester uses smaller datasets and scripts to run your code automatically.

 

Type the following command to obtain the tester folder:

 

hfs -get /user/CS-GY-6513/hw1-test/tester1.tar.gz 

tar -xzvf tester1.tar.gz 

 

Run the following command:

 

chmod -R +x tester 

 

To run the tester (Input path should be directory with the structure mentioned above):

 

./testall_hadoop.sh <INPUTPATH> 

 

The tester will generate a directory called “results” containing the running results (taskX_hadoop.res) indicating whether your code passes the test. You can view the difference between your output and the solution from the file taskX_hadoop.diff Note: Passing the tests does not guarantee your code is correct. Make sure your code runs over the complete datasets.

 

Tasks  

 

Task 1: Write one map-reduce job that joins the 'trips' and 'fare' data (taxi data).

 

The 'fares' and 'trips' data share 4 attributes:  medallion, hack_license, vendor_id, pickup_datetime. 

 

The join MUST BE a reduce-side inner join.

 

Output: A key-value pair per line. Use a “tab” to separate key and value, a comma between multiple keys (and values)

 

key: medallion, hack_license, vendor_id, pickup_datetime

value:  the remaining attributes of 'trips' data in their original order and  

the remaining attributes of 'fare' data in their original order

 

You must respect this ordering requirement!

 

Here’s a sample output with 2 key-value pairs:

00005007A9F30E289E760362F69E4EAD,2C584442C9DC6740767CDE5672C12379,

CMT,2013-08-07 00:55:11    1,N,2013-08-07 00:25:38,1,990,8.9,73.981972,40.764397,-73.927887,40.865353,CRD,26.5,0.5,0.5,5.5,0,33

00005007A9F30E289E760362F69E4EAD,2C584442C9DC6740767CDE5672C12379,

CMT,2013-08-07 02:01:47    1,N,2013-08-07 01:06:05,1,653,3.3,73.983887,40.780346,-73.991646,40.744511,CSH,12.5,0.5,0.5,0,0,13.5

 

The contents of task1 subdirectory looks like:

 

ls -F task1/ 

map.py*        reduce.py* 

 

Here is the command you should use to run task1:

 

hjs -D mapreduce.job.reduces=2 -file ~/<your HW directory>/task1 

-mapper task1/map.py -reducer task1/reduce.py -input /user/CSGY-6513/hw1/fare_data_week1.csv  -input /user/CS-GY-

6513/hw1/trip_data_week1.csv -output /user/netid/task1.out 

 

 

Task 2: Write map-reduce jobs for each of the following sub-tasks, using the output of Task 1 (joined data) as input:

 

(Similar to Task 1, you must use a tab to separate the key and the value in the output tuples.)  

 

a) Find the distribution of fare amounts (fare_amount) for each of the following ranges:  

[0, 20],  

[20.01, 40],  

[40.01, 60],  

[60.01, 80],

[80.01, infinite],  

 

Thus, for each range, give the number of trips whose fare amount falls in that range.

             

Output: A key-value pair per line, where the key is the range, and the value is the number of trips. For example,

 

0,20 100 

     20.01,40   300 

     … 

 

b)    Find the number of trips whose cost is less than or equal to $15 (total_amount).  

 

Output: The number of trips.

 

 

c)    Find the distribution of the number of passengers, i.e., for each number of passengers A, the number of trips that had A passengers.

 

Output: A key-value pair per line, where the key is the number of passengers, and the value is the number of trips. For example, 

 

 

d)    Find the total revenue (for all taxis) and the total amount of tips, per day (from pickup_datetime). Revenue should include the fare amount, tips, and surcharges.

 

Output: A key-value pair per line, where the key is the day YYYY-MM-DD, and the value contains the total revenue and the total tips for that day, in this order.

Use two decimal digits, e.g., 3.02245 should be represented as 3.02. For example,

       2016-01-01    100000.02,11000.00 

       2016-01-02    202000.00,1000.00

e)    For each taxi (medallion) find the total number of trips, and the average number of trips per day. For the average trips per day, use 2 decimal digits.  

Your average should be over all days that the taxi drove, e.g., if the input data has entries for a given taxi on 6 different days, your average should be over 6 days.   

Output: A key-value pair per line, where the key is the medallion, and the value contains the total number of trips and the average number of trips per day.



f)     Find the number of different taxis (medallion) used by each driver (license).

Output: A key-value pair per line, where the key is the driver, and the value is the number of different taxis used by that driver.
 

Task 3 Extra Credit: Try to optimize your map reduce program for Task 1 and report: the strategy you used, statistics about the original and optimized task, and discuss the results (e.g., why the optimization worked, why it did not work) 

If you choose to do the extra credit, include in the zip file one additional folder named “task3” that contains a text/pdf/docx file with your answer.
 

The End