65.连接Hive和Impala-Python

• CDH集群，Anaconda，pip工具，Python包均运行正常
• CM和CDH版本为：5.11.2
• RedHat版本为：7.2
• Python版本为：2.6+ 或者 3.3+
• 非安全集群环境

• 安装Impyla依赖的Python包

[root@ip-186-31-22-86 ~]# pip install bit_array
[root@ip-186-31-22-86 ~]# pip install thrift==0.9.3
[root@ip-186-31-22-86 ~]# pip install six
[root@ip-186-31-22-86 ~]# pip install thrift_sasl
[root@ip-186-31-22-86 ~]# pip install sasl

• 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
• Impyla所依赖的Python包
  • six
  • bit_array
  • thrift (on Python 2.x) orthriftpy (on Python 3.x)
  • thrift_sasl
  • sasl
• 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-186-31-22-86 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

• Python连接Hive（HiveTest.py）

from impala.dbapi importconnect
conn = connect(host='ip-186-31-21-45.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-186-31-26-80.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)

• 在shell命令行执行Python代码测试
  • 测试连接Hive

[root@ip-186-31-22-86ec2-user]# python HiveTest.py

[('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-186-31-22-86 ec2-user]# 

• 测试连接Impala

[root@ip-186-31-22-86ec2-user]# python ImpalaTest.py

[('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-186-31-22-86 ec2-user]# 

常见错误解决方案
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/

解决方案：

[root@ip-186-31-22-86 ec2-user]# yum -y install gcc 
[root@ip-186-31-22-86 ec2-user]# yum install gcc-c++ 

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 
                   ^
compilation terminated.
error: command 'gcc' failed with exit status 1

解决方法：

[root@ip-186-31-22-86 ec2-user]# yum -y install python-devel.x86_64 cyrus-sasl-devel.x86_64

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