Phoenix的团队用了一句话概括Phoenix："We put the SQL back in NoSQL" 意思是：我们把SQL又放回NoSQL去了！这边说的NoSQL专指HBase，意思是可以用SQL语句来查询Hbase，你可能会说：“Hive和Impala也可以啊！”。但是Hive和Impala还可以查询文本文件，Phoenix的特点就是，它只能查Hbase，别的类型都不支持！但是也因为这种专一的态度，让Phoenix在Hbase上查询的性能超过了Hive和Impala！
[root@host1 ~]# cd phoenix-4.2.2-bin/
[root@host1 phoenix-4.2.2-bin]# cd bin
[root@host1 bin]# chmod +x *.py
phoenix可以用4种方式调用
批处理方式
命令行方式
GUI方式
JDBC调用
批处理方式
我们建立sql 名叫 us_population.sql 内容是
CREATE TABLE IF NOT EXISTS us_population ( state CHAR(2) NOT NULL, city VARCHAR NOT NULL, population BIGINT CONSTRAINT my_pk PRIMARY KEY (state, city));
SELECT state as "State",count(city) as "City Count",sum(population) as "Population Sum" FROM us_population GROUP BY state ORDER BY sum(population) DESC;
hbase(main):002:0> scan 'US_POPULATION'
ROW COLUMN+CELL
AZPhoenix column=0:POPULATION, timestamp=1425460467206, value=\x80\x00\x00\x00\x00\x16MG
AZPhoenix column=0:_0, timestamp=1425460467206, value=
CALos Angeles column=0:POPULATION, timestamp=1425460467206, value=\x80\x00\x00\x00\x00:\xAA\xDD
CALos Angeles column=0:_0, timestamp=1425460467206, value=
CASan Diego column=0:POPULATION, timestamp=1425460467206, value=\x80\x00\x00\x00\x00\x13(t
CASan Diego column=0:_0, timestamp=1425460467206, value=
CASan Jose column=0:POPULATION, timestamp=1425460467206, value=\x80\x00\x00\x00\x00\x0D\xEB\xCC
CASan Jose column=0:_0, timestamp=1425460467206, value=
ILChicago column=0:POPULATION, timestamp=1425460467206, value=\x80\x00\x00\x00\x00+_\x96
ILChicago column=0:_0, timestamp=1425460467206, value=
NYNew York column=0:POPULATION, timestamp=1425460467206, value=\x80\x00\x00\x00\x00|A]
NYNew York column=0:_0, timestamp=1425460467206, value=
PAPhiladelphia column=0:POPULATION, timestamp=1425460467206, value=\x80\x00\x00\x00\x00\x16S\xF1
PAPhiladelphia column=0:_0, timestamp=1425460467206, value=
TXDallas column=0:POPULATION, timestamp=1425460467206, value=\x80\x00\x00\x00\x00\x12\x85\x81
TXDallas column=0:_0, timestamp=1425460467206, value=
TXHouston column=0:POPULATION, timestamp=1425460467206, value=\x80\x00\x00\x00\x00\x1E\xC5F
TXHouston column=0:_0, timestamp=1425460467206, value=
TXSan Antonio column=0:POPULATION, timestamp=1425460467206, value=\x80\x00\x00\x00\x00\x13,=
TXSan Antonio column=0:_0, timestamp=1425460467206, value=
10 row(s) in 0.2220 seconds
会发现
之前定义的PRIMARY KEY 为 state, city ，于是Phoenix就把你输入的state 和 city的值拼起来成为rowkey
其他的字段还是按照列名去保存，默认的列簇为 0
还有一个0:_0 这个列是没有值的，这个是Phoenix处于性能方面考虑增加的一个列，不用管这个列
命令行方式
然后执行sqlline.py
$ ./sqlline.py localhost
可以进入命令行模式
0: jdbc:phoenix:localhost>
退出命令行的方式是执行 !quit
0: jdbc:phoenix:localhost>!quit
命令开头需要一个感叹号，使用help可以打印出所有命令
0: jdbc:phoenix:localhost> help
!all Execute the specified SQL against all the current connections
!autocommit Set autocommit mode on or off
!batch Start or execute a batch of statements
!brief Set verbose mode off
!call Execute a callable statement
!close Close the current connection to the database
!closeall Close all current open connections
!columns List all the columns for the specified table
!commit Commit the current transaction (if autocommit is off)
!connect Open a new connection to the database.
!dbinfo Give metadata information about the database
!describe Describe a table
!dropall Drop all tables in the current database
!exportedkeys List all the exported keys for the specified table
!go Select the current connection
!help Print a summary of command usage
!history Display the command history
!importedkeys List all the imported keys for the specified table
!indexes List all the indexes for the specified table
!isolation Set the transaction isolation for this connection
!list List the current connections
!manual Display the SQLLine manual
!metadata Obtain metadata information
!nativesql Show the native SQL for the specified statement
!outputformat Set the output format for displaying results
(table,vertical,csv,tsv,xmlattrs,xmlelements)
!primarykeys List all the primary keys for the specified table
!procedures List all the procedures
!properties Connect to the database specified in the properties file(s)
!quit Exits the program
!reconnect Reconnect to the database
!record Record all output to the specified file
!rehash Fetch table and column names for command completion
!rollback Roll back the current transaction (if autocommit is off)
!run Run a script from the specified file
!save Save the current variabes and aliases
!scan Scan for installed JDBC drivers
!script Start saving a script to a file
!set Set a sqlline variable
!sql Execute a SQL command
!tables List all the tables in the database
!typeinfo Display the type map for the current connection
!verbose Set verbose mode on
create 'employee','company','family'
put 'employee','row1','company:name','ted'
put 'employee','row1','company:position','worker'
put 'employee','row1','family:tel','13600912345'
put 'employee','row2','company:name','michael'
put 'employee','row2','company:position','manager'
put 'employee','row2','family:tel','1894225698'
scan 'employee'
声明： 本文只为方便我个人查阅和理解，详细的分析以及源代码请移步 原作者的博客http://chjavach.iteye.com/
public class Singleton {
}
/*
* 懒汉模式。注意，getInstance如果在多线程环境中调用，需要加上synchronized，否则存在线程不安全问题
*/
class LazySingleton
这个月公司安排我一个人做iOS客户端开发，由于急着用，我先发布一个版本，由于第一次发布iOS应用，期间出了不少问题，记录于此。
1、使用Application Loader 发布时报错：Communication error.please use diagnostic mode to check connectivity.you need to have outbound acc
/*
2013年3月15日15:16:24
malloc 就memory(内存) allocate(分配)的缩写
本程序没有实际含义，只是理解使用
*/
# include <stdio.h>
# include <malloc.h>
int main(void)
{
int i = 5; //分配了4个字节 静态分配
int * p
http://wiki.sdn.sap.com/wiki/display/BOBJ/Optimize+query+with+Query+Stripping+in+Web+Intelligence
and a very straightfoward video
http://www.sdn.sap.com/irj/scn/events?rid=/library/uuid/40ec3a0c-936
