I am learning hadoop map reduce using word count example , please see the diagram attached : My questions are regarding how the parallel processing actually happens , my understanding/questions below , please correct me if i am wrong : Split step : T
I have a table in hive called purchase_data that has a list all the purchases made. I need to query this table and find the cust_id, product_id and price of the most expensive product purchased by a customer. The data in purchase_data table looks lik
I am looking to evaluate the possibility of using Cassandra, BigTable, or a Hadoop-solution. Are there any places that have an up-to-date comparison on how these three compare and perform on a set of benchmark tests? I found a few from perhaps five y
Trying to start hadoop 2.7.3 services datanode is not starting: java.io.IOException: Incompatible clusterIDs in /opt/hadoop/tmp/dfs/data: namenode clusterID = CID-4808098e-de31-469d-9761-9a4558fdaf70; datanode clusterID = CID-492135f3-fc08-46f1-a574-
I am installing HAWQ on RedHat servers provisioned on Amazon EC2. I already have HDP 2.3 setup on the cluster. I have cloned HAWQ from Github. First I run ./configure --prefix=/opt/hawq. In the second step, I run make. The dependencies are compiling
I am trying to create a Hive UDAF to find most frequently appearing column (string) value (not single character or substring, exact column value is used) . Assume that the following is my table called my_table (dashes are used for separating columns
I am new to hadoop and pig. I am trying to run a sample pig script in a CentOS6 enviroment on VMWARE: records = LOAD '2013_subset.csv' USING PigStorage(',') AS (Year,Month,DayofMonth,DayOfWeek,DepTime,CRSDepTime,ArrTime,\ CRSArrTime,UniqueCarrier,Fli
This is my hive table: course dept subject status btech cse java pass btech cse hadoop fail btech cse cg detained btech cse cc pass btech it daa pass btech it wt pass btech it cnn pass mba hr hrlaw pass mba hr hrguid absent mtech cs java pass mtech c
when i run this command on master note in hadoop [email protected]:~$ hive However Hadoop multinode is working fine it shows following errors: Logging initialized using configuration in jar:file:/usr/local/apache-hive-1.2.1-bin/lib/hive-common-1.2.
I'm new on Impala, and I'm trying to understand how to delete records from a table... I've tried looking for delete commands, but didn't quite find understandable instructions... This is my table structure: create table Installs (BrandID INT, Publish
I am trying to run simple kafka producer consumer example on HDP but facing below exception. [2016-03-03 18:26:38,683] WARN Fetching topic metadata with correlation id 0 for topics [Set(page_visits)] from broker [BrokerEndPoint(0,sandbox.hortonworks.
I am going through the lambda architecture and understanding how it can be used to build fault tolerant big data systems. I am wondering how batch layer is useful when everything can be stored in realtime view and generate the results out of it? is i
Does Hive get_json_object function parse each JSON object for field resolution, even after we create a view on top of JSON data? We are having issues reading our JSON Data with SERDE. For this reason we want to use this udf and create views on top of
I have multiple compressed files and each compressed file contains 8 xml files of size 5-10kb. I took this data for testing purpose otherwise live data has 1000s of xml files. I wrote map only program to uncompress the compressed file for(FileStatus
I am using Map Reduce framework. Let's say this is the input list [A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P ,Q, R, S, T, U, V, W, X, Y, Z] and my Mapper produces the following output: <"Key 1" : A> <"Key 2" : B> <&
We have a table in which we want to store data for the top 100 pages. So if the destination table top100Pages has uid string, mid string, pageurl string, plays string, device string To fill this table, I can run: SELECT uid, mid,pageurl,sum(plays),de
I am trying to connect to hive installed in my machine through Beeline client. when I give the 'beeline' command & connect to Hive, the client is asking for user name & password !connect jdbc:hive2://localhost:10000/default I have no idea what is
I have installed and configured Hadoop 2.5.2 for a 10 node cluster. 1 is acting as masternode and other nodes as slavenodes. I have problem in executing hadoop fs commands. hadoop fs -ls command is working fine with HDFS URI. It gives message "ls: `.
I am just using my 6GB RAM laptop. I just want to know if the 'Fair Scheduler' will or can work to single-node cluster.Yes, as there can be multiple mappers and reducers on one node, so the Fair Scheduler will still prioritise.
Could someone please explain to me what is the difference between Hadoop Streaming vs Buffering? Here is the context I have read in Hive : In every map/reduce stage of the join, the last table in the sequence is streamed through the reducers whereas
I am trying to run following MapReduce code in my local machine: https://github.com/Jeffyrao/warcbase/blob/extract-links/src/main/java/org/warcbase/data/ExtractLinks.java However, I met this exception: [main] ERROR UserGroupInformation - PriviledgedA
I wanted to call sqoop export command in my pig script, Basically once I stored my result immediatlyy i wanted to call sqoop export cmd. Is it possible ? If Yes please let me know how to call . Thanks SelvamNo, you can't do Sqoop export from Apache P
We are testing Hive and Hadoop for digging in our data and I installed a while back Hadoop 1.2.1 and Hive 0.11 (was the stable version) Test server is 4 cores and 16GB of ram. Now I wanted to know if switching to Hive 0.12 and Hadoop 2.2 is worth the
I am trying Hadoop 2 High Availability for HDFS. I set up passwordless ssh connection among NameNodes under user hafence. That I verified - and it works. However I am getting following (Permission Denied) when using this sshfence setup. 2014-01-20 12
I have a problem to solve and was wondering if I am right to use something like Hadoop for this problem to distribute it across multiple nodes or use something else.. The Problem: I have a very large database table with potentially a huge amount of r
Is it possible to perform lag, lead operations on the data stored in Hive ? Any pointers would be greatly appreciated !!!Right now you need to use the SQLWindowing extensions to perform lag, lead, and other windowing functions. In the future, this wi
I have found somebody talks libhdfs does not support read/write gzip file at about 2010. I download the newest hadoop-2.0.4 and read hdfs.h. There is also no compressing arguments. Now I am wondering if it supports reading compressed file now? If it
Is it possible to sort a huge text file lexicographically using a mapreduce job which has only map tasks and zero reduce tasks? The records of the text file is separated by new line character and the size of the file is around 1 Terra Byte. It will b
I have downloaded latest stable release of Hive, when I start /usr/local/hive/bin/hive it gives me this error: Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/hadoop/hive/conf/HiveConf at java.lang.Class.forName0(Native Met
I'm trying to retrieve rows with in range, using Filter List but I'm not successful. Below is my code snippet. I want to retrieve data between 1000 and 2000. HTable table = new HTable(conf, "TRAN_DATA"); List<Filter> filters = new ArrayLis