如何使用Python Impyla客户端连接Hive和Impala

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1.文档编写目的

继上一章讲述如何在CDH集群安装Anaconda&搭建Python私有源后，本章节主要讲述如何使用Pyton Impyla客户端连接CDH集群的HiveServer2和Impala Daemon，并进行SQL操作。

• 内容概述

1.依赖包安装

2.代码编写

3.代码测试

• 测试环境

1.CM和CDH版本为5.11.2

2.RedHat7.2

• 前置条件

1.CDH集群环境正常运行

2.Anaconda已安装并配置环境变量

3.pip工具能够正常安装Python包

4.Python版本2.6+ or 3.3+

5.非安全集群环境

2.Impyla依赖包安装

Impyla所依赖的Python包

• six
• bit_array
• thrift (on Python 2.x) orthriftpy (on Python 3.x)
• thrift_sasl
• sasl

1.首先安装Impyla依赖的Python包

[root@ip-172-31-22-86 ~]# pip install bit_array
[root@ip-172-31-22-86 ~]# pip install thrift==0.9.3
[root@ip-172-31-22-86 ~]# pip install six

[root@ip-172-31-22-86 ~]# pip install thrift_sasl

[root@ip-172-31-22-86 ~]# pip install sasl

注意：thrift的版本必须使用0.9.3，默认安装的为0.10.0版本，需要卸载后重新安装0.9.3版本，卸载命令pip uninstall thrift

2.安装Impyla包

impyla版本，默认安装的是0.14.0，需要将卸载后安装0.13.8版本

 [root@ip-172-31-22-86 ec2-user]# pip install impyla==0.13.8
Collecting impyla
  Downloading impyla-0.14.0.tar.gz (151kB)
    100% |████████████████████████████████| 153kB 1.0MB/s 
Requirement already satisfied: six in /opt/cloudera/parcels/Anaconda-4.2.0/lib/python2.7/site-packages (from impyla)
Requirement already satisfied: bitarray in /opt/cloudera/parcels/Anaconda-4.2.0/lib/python2.7/site-packages (from impyla)
Requirement already satisfied: thrift in /opt/cloudera/parcels/Anaconda-4.2.0/lib/python2.7/site-packages (from impyla)
Building wheels for collected packages: impyla
  Running setup.py bdist_wheel for impyla ... done
  Stored in directory: /root/.cache/pip/wheels/96/fa/d8/40e676f3cead7ec45f20ac43eb373edc471348ac5cb485d6f5
Successfully built impyla
Installing collected packages: impyla
Successfully installed impyla-0.14.0

3.编写Python代码

Python连接Hive（HiveTest.py）

from impala.dbapi importconnect

conn = connect(host='ip-172-31-21-45.ap-southeast-1.compute.internal',port=10000,database='default',auth_mechan

ism='PLAIN')

print(conn)

cursor = conn.cursor()

cursor.execute('show databases')

print cursor.description # prints the result set's schema

results = cursor.fetchall()

print(results)

cursor.execute('SELECT * FROM test limit 10')

print cursor.description # prints the result set's schema

results = cursor.fetchall()

print(results)

Python连接Impala（ImpalaTest.py）

from impala.dbapi importconnect

conn = connect(host='ip-172-31-26-80.ap-southeast-1.compute.internal',port=21050)

print(conn)

cursor = conn.cursor()

cursor.execute('show databases')

print cursor.description # prints the result set's schema

results = cursor.fetchall()

print(results)

cursor.execute('SELECT * FROM test limit 10')

print cursor.description # prints the result set's schema

results = cursor.fetchall()

print(results)

4.测试代码

在shell命令行执行Python代码测试

1.测试连接Hive

_root@ip-172-31-22-86_ec2-user# python HiveTest.py

<impala.hiveserver2.HiveServer2Connection_object at 0x7f66eee00250>_

('database_name', 'STRING', None, None, None, None, None)

('default',)

('test.s1', 'STRING',None, None, None, None, None), ('test.s2', 'STRING', None, None, None, None, None)

('name1', 'age1'), ('name2', 'age2'), ('name3', 'age3'), ('name4', 'age4'), ('name5', 'age5'), ('name6', 'age6'), ('name7', 'age7'), ('name8', 'age8'), ('name9', 'age9'), ('name10', 'age10')

[root@ip-172-31-22-86 ec2-user]#

2.测试连接Impala

_root@ip-172-31-22-86_ec2-user# python ImpalaTest.py

<impala.hiveserver2.HiveServer2Connection_object at 0x7f7e1f2cfad0>_

('name', 'STRING', None, None, None, None, None), ('comment', 'STRING', None, None, None, None, None)

('_impala_builtins', 'Systemdatabase for Impala builtin functions'), ('default', 'Default Hive database')

('s1', 'STRING', None, None, None,None, None), ('s2', 'STRING', None, None, None,None, None)

('name1', 'age1'), ('name2', 'age2'), ('name3', 'age3'), ('name4', 'age4'), ('name5', 'age5'), ('name6', 'age6'), ('name7', 'age7'), ('name8', 'age8'), ('name9', 'age9'), ('name10', 'age10')

[root@ip-172-31-22-86 ec2-user]#

5.常见问题

1.错误一

building 'sasl.saslwrapper' extension
    creating build/temp.linux-x86_64-2.7
    creating build/temp.linux-x86_64-2.7/sasl
    gcc -pthread -fno-strict-aliasing -g -O2 -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -Isasl -I/opt/cloudera/parcels/Anaconda/include/python2.7 -c sasl/saslwrapper.cpp -o build/temp.linux-x86_64-2.7/sasl/saslwrapper.o
    unable to execute 'gcc': No such file or directory
    error: command 'gcc' failed with exit status 1
    
    ----------------------------------------
Command "/opt/cloudera/parcels/Anaconda/bin/python -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-kD6tvP/sasl/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('rn', 'n');f.close();exec(compile(code, __file__, 'exec'))" install --record /tmp/pip-WJFNeG-record/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /tmp/pip-build-kD6tvP/sasl/

解决方法：

[root@ip-172-31-22-86 ec2-user]# yum -y install gcc 
[root@ip-172-31-22-86 ec2-user]# yum install gcc-c++ 

2.错误二

gcc -pthread -fno-strict-aliasing -g -O2 -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -Isasl -I/opt/cloudera/parcels/Anaconda/include/python2.7 -c sasl/saslwrapper.cpp -o build/temp.linux-x86_64-2.7/sasl/saslwrapper.o
cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC but not for C++ [enabled by default]
In file included from sasl/saslwrapper.cpp:254:0:
sasl/saslwrapper.h:22:23: fatal error: sasl/sasl.h: No such file or directory
#include <sasl/sasl.h>
                   ^
compilation terminated.
error: command 'gcc' failed with exit status 1

解决方法：

[root@ip-172-31-22-86 ec2-user]# yum -y install python-devel.x86_64 cyrus-sasl-devel.x86_64

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