Alias command

The ALIAS command reads different resources (data) using a fixed resource name in MapReduce or UDF without modifying the code.

Command format:
ALIAS <alias>=<real>;


Create alias for a resource.

ADD TABLE src_part PARTITION (ds='20121208') AS res_20121208;
ADD TABLE src_part PARTITION (ds='20121209') AS res_20121209;
ALIAS resName=res_20121208;
jar -resources resName -libjars work.jar -classpath ./work.jar args ... ;//job 1
ALIAS resName=res_20121209;
jar -resources resName -libjars work.jar -classpath ./work.jar args ... ;//job 2
In the preceding example, resource alias resName refers to different resource tables in two jobs. Different data can be read without modifying the code.

Cost SQL

Command format:
cost sql <SQL Sentence>;


Estimate an SQL measurement message, including the size of the input data, the number of UDFs, and the SQL complexity level.
Note Use the following information for reference purpose only. Refrain from using it as an actual charging standard.
odps@ $odps_project >cost sql select distinct project_name, user_name from meta.m_security_users distribute by project_name sort by project_name;  
ID = 20150715113033121xxxxxxxx
Input:65727592 Bytes