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Tuesday, October 21, 2014

executing sequence of JOIN, WHERE, GROUP BY HAVING clauses in Hive

Understanding the sequence of executing sequence of clauses in Hive is very helpful for optimizing query. It will be idea if we can make every inter steps to generate data set as small as possible. The order of executing part of a query:

  1. FROM & JOINs determine & filter rows
  2. WHERE more filters on the rows
  3. GROUP BY combines those rows into groups
  4. HAVING filters groups
  5. ORDER BY arranges the remaining rows/groups

Monday, October 6, 2014

install vagrant on CentOS

[root@vmhost01 vagrant]# wget

[root@vmhost01 vagrant]# yum install vagrant_1.6.3_x86_64.rpm 

[root@vmhost01 vagrant]# vagrant plugin install vagrant-mutate

[root@vmhost01 vagrant]# mkdir /vm1/vm10

[root@vmhost01 vagrant]# cd /vm1/vm10

[root@vmhost01 vm10]# vagrant box add centos65
==> box: Adding box 'centos65' (v0) for provider: 
    box: Downloading:
==> box: Successfully added box 'centos65' (v0) for 'virtualbox'!

[root@vmhost01 vm10]# vagrant mutate centos65 libvirt
You have qemu 0.12.1 installed. This version cannot read some virtualbox boxes. If conversion fails, see below for recommendations.
Converting centos65 from virtualbox to libvirt.
The box centos65 (libvirt) is now ready to use.
[root@vmhost01 vm10]# pwd
[root@vmhost01 vm10]# vagrant init centos65
A `Vagrantfile` has been placed in this directory. You are now
ready to `vagrant up` your first virtual environment! Please read
the comments in the Vagrantfile as well as documentation on
`` for more information on using Vagrant.

[root@vmhost01 vm10]# vagrant plugin install vagrant-libvirt  --plugin-version 0.0.19

[root@vmhost01 vm10]#  vagrant up --no-parallel