现在的位置: 首页 > 综合 > 正文

DataStage Parallel routines made really easy

2018年01月15日 ⁄ 综合 ⁄ 共 4213字 ⁄ 字号 评论关闭
 DataStage is a powerful ETL tool with lot of inbuilt stages/routines
which can do most of the functionalities required; for those things
DataStage EE can’t do, there are parallel routines which can be
written in C++.

This primer can teach you how you can create a parallel routine in
few minutes, regardless of whether or not you are a C/C++ programmer.
But to write some real good codes you might have to learn some C++
programming. Starting C programming with Linux is a good link to start with.

Before we begin, few points to be noted:

Parallel routines are C++ components built and compiled
external to DataStage. Note - they must be compiled as C++ components,
not C.

This C++ program should be without main() and compiled using the
compiler option specified under “APT_COMPILEOPT” which can be found
under Administrator parameter option and create an object (*.o). This
will create runtime libraries which are compiled code, without main ie.
non self-contained executable file.

Compiler and compiler options can be found in

DataStage --> Administrator --> Properties --> Environment --> Parallel --> Compiler

Ex: compiler = g++

compiler options = -O -fPIC -Wno-deprecated –c

Compile command syntax

Compiler : compiler options : {filename with extenstion}

Ex: g++ -O -fPIC -Wno-deprecated -c {filename with extenstion}

Here's the typical sequence of steps for creating a DataStage parallel routine:

Create --> Compile --> Link --> Execute

1) Create

Create a C++ program with main()

Test it and if successful remove the main()

2) Compile

Compile using the compiler option specified under
“APT_COMPILEOPT”. Note:Compiler and compiler options can be found
in "DataStage --> Administrator --> Properties --> Environment
--> Parallel --> Compiler" and create an object (*.o) file and
put this object file onto this directory.

3) Link

Link the above object (*.o) to a DataStage Parallel routine by making the relevant entries in General tab:

Routine Name: {Parallel Routine Name}

Type: External Function

Object Type: Object / Library

External subroutine name: {Function Name specified inside your C++ program}

Library Path: {Specified in 2) Compile section + object (*.o) file name }

Also specify the Return Type and if you have any input parameters to be passed specify that in Arguments tab.

4) Execute

Now your parallel routine will be available inside your job. Include and compile your job and execute.

Step by step Example:

Creating a shared object

1) Create a C++ program with main()

Create a text file with cpp extn (Ex: OBJTEST.cpp )

Ex:

#include <stdlib.h>

#include <stdio.h>

int main()

{

char* OutStr;

OutStr="Hello World - Object Testing";

printf(OutStr);

return 0;

}

Test this program

Copy your compiler specification from

"DataStage --> Administrator --> Properties --> Environment --> Parallel --> Compiler"

and compile the created C++ program

Syntax: g++ program.cpp –o program

Ex: g++ OBJTEST.cpp -o OBJTEST

Run/Execute using the below command

Syntax: ./program

./OBJTEST

Output --> Hello World - Object Testing

If you get above output, that means your program is successfully executed.

Re-write the program without main()

Ex:

#include <stdlib.h>

#include <stdio.h>

char * ObjTestOne()

{

char* OutStr;

OutStr="Hello World - Object Testing";

return OutStr;

}

2)Compile the program

Get compiler and compiler options from:

DataStage --> Administrator --> Properties --> Environment --> Parallel --> Compiler

Ex: compiler = g++

compiler options = -O -fPIC -Wno-deprecated –c

Compile command syntax

Compiler : compiler options : {filename with extenstion}

Ex: g++ -O -fPIC -Wno-deprecated -c {filename with extenstion}

Execute the below command:

g++ -O -fPIC -Wno-deprecated –c OBJTEST.cpp

This will make and object file with .o extn -->Ex: OBJTEST.o

Move this object file to any of the Library Path of your preference:

Ex: /datastage/Ascential/DataStage/PXEngine/lib

I usually put in "lib" directory. You can locate your "lib" directory from Library Path (LD_LIBRARY_PATH).

3) Link

Link the above object (*.o) to a DataStage Parallel routine.

In the repository pallet “right click” and chose “New parallel routine” and make these entries in the General tab:

Routine Name: {Parallel Routine Name} Ex: OBJECTTEST

Type: External Function

Object Type: Object

External subroutine name: {Function Name specified inside your C++ program}

Ex: ObjTestOne (Remember? This is the function name we replaced for main() ie. char * ObjTestOne() )

Library Path: {Specified in Compile section + object (*.o) file name }

Ex: /datastage/Ascential/DataStage/PXEngine/lib/OBJTEST.o

Return Type: char*

Note:As we don’t have any input parameters to be passed we are not making any entries in Arguments tab.

Now save and close the window.

4) Execute

Create a test job and call this parallel routine inside your job.

Ex: Row Generator --> Transformer --> Sequential File

In the transformer call this routine in your output column derivation. Compile and run the job.

抱歉!评论已关闭.