I encountered a piece of code in Apache Hive, such as regexp_extract(input,'[0-9] *’,0), can someone explain to me what this code does? Thank you Starting from the Hive manual DDL, it returns the
Tag: Hadoop
MapReduce on Hadoop said “output file already exists”
I ran a wordcount example using Mapreduce for the first time, and it worked. Then, I stopped the cluster, started it temporarily, and followed the same steps. This error is displayed:
10P:/$
Hadoop fs -cp, said that the file does not exist?
The new.txt file is certain; I don’t know why when I try to enter the hdfs directory, it says the file does not exist.
deepak@deepak:/$cd $HOME/fs
deepak@deepak:~/fs$ls
new.txt
deepak@deepak:
Hadoop sequence data access
According to Hadoop authoritative guidelines:
HDFS is a filesystem designed for storing very large files with
streaming or sequential data access patterns
What is streaming or sequenti
Hadoop pseudo-distribution
The virtual machine creation and basic linux configuration are skipped, and the key configuration for building a pseudo-distributed hadoop cluster on a single node is recorded.
Get the hadoop
Mac deployed Hadoop3 (pseudo-distributed)
Environmental information Operating system: macOS Mojave 10.14.6 JDK: 1.8.0_211 (installation location: /Library /Java/JavaVirtualMachines/jdk1.8.0_211.jdk/Contents/Home) hadoop: 3.2.1
In “S
(Heavy pound) fastest Hadoop fully distributed operation
1. Prepare the virtual machine Clone 3 linux virtual machines, only the machine with centos minimal mode installed
Network allocation table
Host name
IP address
hadoop1
<
9, Hadoop-HDFS Overview
1. Background and definition of HDFS generation Background generation
As the amount of data becomes larger and larger, it is stored in a system If you don’t have all the data, you need to all
6-Hadoop operating mode (fully distributed) (on)
Note: In actual production and development, fully distributed is used
1) Prepare 3 clients (close firewall, static ip, host name)
2) Install JDK
3) Configure environment Variables