Friday, 15 July 2011

Microsoft SQL Server code-named 'Denali' - Community Technology Preview 3 : Data Flow

Below you can find my review on the Data Flow part of CTP 3 which I will extend the next few days.This review is part of an overall review of Microsoft SQL Server code-named 'Denali' - Community Technology Preview 3.

Data Flow

Flexible Authoring
Change in CTP 1: It's now possible to edit a component even when its input path is disconnected.

Simplified Data Viewer
The Data Viewer can now be configured directly from the Data Flow Path editor. The data viewer only supports a grid view, the histogram and scatter plot views have been removed (but who has ever used them?).
An other time saver: just one right and one left click.

I only get a little error message when I execute the task and close the data viewer.
Error message when closing data viewer

Source & Destination Assistant
Added in CTP 1: the Source Assistant and Destination Assistant. Feels a little bit like SSIS for Dummies... and there isn't a flatfile target.
They are extra.

After the OK, you will get the regular screens.

Grouping in dataflow
Very useful for large dataflows is the new collapsible grouping option.
Dataflow grouping

Data Correction / DQS Cleansing
The new data flow object I mentioned in my CTP 1 review is gone (was not yet working there), but a new transformation has been added: DQS Cleansing. Will check it out later on. See also Data Quality Services.
DQS Cleansing

I expected a better editor. Unfortunately no improvements yet... See/vote this request at Microsoft Connect.
Still the user unfriendly editor

Microsoft SQL Server code-named 'Denali' - Community Technology Preview 3 : Control Flow

Below you can find my review on the Control Flow part of CTP 3 which I will extend the next few days. This review is part of an overall review of Microsoft SQL Server code-named 'Denali' - Community Technology Preview 3.

Control Flow

New icons
Changed in CTP 1. There are new icons for the tasks with rounded corners. Just nicer!
Rounded corners

SSIS Toolbox
Changed in CTP 1 and change again in CTP 3. They regrouped the items with some new categories. And new custom tasks and components should automatically appear in the toolbox. There are some new tasks (like Expression Task) and some have disappeared (Execute DTS 2000 Package Task, ActiveX Script Task, have you ever used them?). One thing is a little confusing: there is a Toolbox and an SSIS Toolbox available (the first one is empty for SSIS).
SSIS Toolbox

Foreach Loop
Changed in CTP 1. Finally the Foreach File enumerator configuration is instantly visable (personal irritation).
SSIS 2008: where is my configuration?

Execute Package
Changed in CTP 1: ReferenceType has been added to the Execute Package Task. Which you can use to select a package from your current project. If you choose External Reference, you will get the SQL Server / File system choice.
Package Reference Type

Expression Task
With this new task you can fill variables. An activity you probably previously did with a Script Task.
One little weird thing is that you have to name *1 (see picture) the variable that you want to fill in the expression. It would be nicer if you could select the variable in a drop down and then add the expression in a separate field.
Expression Task: Notice the new/extra folder for system variables (*2)

Wednesday, 13 July 2011

Microsoft SQL Server code-named 'Denali' - Community Technology Preview 3

It took Microsoft a while since CTP 1, but CTP 3 has been released this morning and there are some exciting new features. You can read a great review at SSIS Junkie. And you should also read the SSIS Team Blog. Below you can find my review which I will extend the next few days.

Review parts:
General changes
Control Flow changes
Data Flow changes


Visual Studio 2010
CTP 3 finally uses Visual Studio 2010. CTP 1 was still using Visual Studio 2008.
Visual Studio 2010!

Undo & Redo
Added in CTP 1, but probably one of the best new features.
They really work

Cut & Paste
Added in CTP 1. If you paste with your mouse, the item will be pasted at your mouse position instead of somewhere below. This too will make your developer life easier.

Added in CTP 1. Very handy zoom function in the lower right corner which fades when not active.

Variables and there scope
The most annoying part of variables was that when you created a new variable the selected task in the Control Flow became the default scope and you where not allowed to change that. Both flaws have been solved!

Although I selected a Foreach Loop Container, the package became the scope!
Default scope: the package!

And if you want to use the Foreach Loop Container as a scope, you can use the Move Variable button the change the scope!
Change scope!

One little bug (?). If you change the scope. The variable will be renamed and the Foreach Loop Container gets an InvalidVariableMappings warning.
Notice the extra "1"


Solution Explorer
The Solution Explorer has changed. No more Data Sources and Data Source Views. I have used them once in a project I didn't started. So I won't miss them. But they added an Connection Managers item instead. Those connections are available in all packages.

Solution Explorer SSIS 2008

Solution Explorer SSIS Denali CTP 3

If you add a new connection manager in the Solution Explorer it is automaticly added (in bold) to the Connection Managers in the bottum left of your screen.
Connection Managers

They also added the Project Parameters to the Solution Explorer. I will review the parameters later on.

New Expressions
The new LEFT expression was already added in CTP 1, but there are two new handy expressions for handling arrays. TOKEN returns the specified occurrence of a token in a string. If the column ColWithArray contains "abc,def,ghi" then TOKEN(ColWithArray,",",2) will return "def" and TOKENCOUNT(ColWithArray,",") will return 3.

You can now use Enter instead of Ctrl + Enter in the annotations, but there is an error when trying to copy and paste (I thought I had already seen that in CTP1, but not sure).
Error when trying copy and paste

Sunday, 10 July 2011

Create a package template in SSIS

I have a package that I want to use as a basis for all my packages. How do I create a package template in SSIS.

Creating a template for SSIS is very simple:

1) Create package
Create a package that you want to use as a template. Add for example loggings, configurations or connections that you want to use for all packages. Give it a suitable name.

2) Copy package
Copy the saved package to the DataTransformationItems folder from Visual Studio:
C:\Program Files (x86)\Microsoft Visual Studio 9.0\Common7\IDE\PrivateAssemblies\ProjectItems\DataTransformationProject\DataTransformationItems\
C:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE\PrivateAssemblies\ProjectItems\DataTransformationProject\DataTransformationItems\
C:\Program Files\Microsoft Visual Studio 8\Common7 \IDE\PrivateAssemblies\ProjectItems\DataTransformationProject\DataTransformationItems

That's all!

3) Using template
In your project go to the Solution Explorer and right click on the project and choose Add, New Item...
Solution Explorer: Add new item...

Now choose your template and give the package a suitable name (*).
Select your new template

4) Change ID
Your newly created package gets the same package GUID as the original template file. You have to generate a new GUID for you package. If you don't do that, things like logging could be a problem because you can't distinguish the packages by ID. Also see/vote for this feedback at Microsoft Connect
Generate new ID / GUID

(*) An other bug is that when you enter a new name in the wizard, it only changes the filename and not the internal object name. It's better to just use the given default name and then rename it in the Solution Explorer. Renaming in the Solution Explorer will also give you the option to rename the internal object name.

Note: Changes made in a template file doesn't effect existing packages based on that template.

Saturday, 9 July 2011

Balanced Data Distributor

A few weeks ago Microsoft quietly released a new Data Flow transformation for SSIS 2008 and 2008 R2: Balanced Data Distributor. This transform takes a single input and distributes the incoming rows to one or more outputs uniformly via multi-threading.

UPDATE: 2012 version has been released

How does it work? If you load a large file in to a staging table it looks something like the flow below. Out of the box SSIS doesn't process this via multi-threading; one flow, one thread.
Single flow

The Balanced Data Distributor introduces parallelism in the data flow and multi-processor and multi-core servers will profit from that new feature. SSIS can now distribute the work over multiple threads which makes your data flow a lot faster.

Balanced Data Distributor

When do you use this new Balanced Data Distributor?
- You have a large amount of data coming in
- You can read faster than you can process it in your data flow
- The destination supports parallelism (a flat file target wont work because it gets locked)
- Your package runs on a multi-processor and multi-core server
More info about that and the bottlenecks in this MSDN Blog.

If your destination doesn't support parallelism or you want for example to aggregate all data then you can use a Union All. Now only part of the flow is multi-threading.
Part of the data flow is multi-threading.

Alternatives for Balanced Data Distributor.
There are a few constructions already available in SSIS to get parallelism.
1) A Conditional Split with a modulo expression to split the rows into multiple streams
2) A Script Component with multiple outputs and a modulo construction in .Net
Conditional Split with a Modulo expression

Example of a modulo expression

For more details about parallelism with a Condition Split can be found in this great blog article from fellow Dutchman Henk van der Valk.

A nice start to get parallelism into SSIS, but there already where some possibilities. Hopefully this component wont be necessary in the future versions of SSIS. An automatic form of multi-threading would be nice!
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