Recently I've been doing a lot with IFS. It seems like the ideal solution to create and present forms, far more capable than regular SharePoint list forms and far less complicated than coding forms in Visual Studio.
But there are some caveats to this beauty, which begin to appear just after you've just got yourself and your client in a good mood by finding all of your requirements covered by Infopath: Performance.
We've ran into a number of problems after publishing some more 'complex' forms, these are some examples:
- A repeating section does not persist more than 9 items
- IE crashes while filling out the form, totaly random
- Rendering the form takes >60 seconds, taking 99% CPU and +600mb RAM
- Uploading the form results in a error (both Central Admin and STSADM)
- The design checker times-out, InfoPath cannot open the form
Most of these problems occur at the browser. It's interesting to note that the server does not have any trouble serving the forms. Rendering the form in the browser is done fully dynamically. With complex and large forms this can lead to bad performance and functional issues. Uploading complex forms can take up to 30 minutes (depending on the time-outs you've defined in SharePoint).
This is a list of best practices to keep you in control of performance. There's definitely not one golden solution, you should look for a balance throughout your form.
1. Use IE7 instead of IE6
IE7 used a new scripting engine, which is far more efficient with resources. While rendering forms this could save you hundreds of mb's and up to 50% CPU. In practice forms will render up to 10x faster in IE7.
2. Deploy the hotfix for conditional formatting issues (must have!)
Conditional visibility logic has some known performance problems. A hotfix is available http://support.microsoft.com/kb/937206, which is manifested in a modified 250K initial download (de core.js) when accessing Forms Services the first time. The performance issue is related to the IE Script Engine and occurs at the browser level, not server-side.
I've tested a form before and after installing the hotfix:
| |
IE6.0* |
IE7.0* |
| |
Without hotfix |
With hotfix |
Without hotfix |
With hotfix |
|
Rendering |
65 sec |
15 sec |
14 sec |
13 sec |
| CPU Load |
99% |
99% |
50% |
50% |
| RAM |
60mb |
30mb |
68mb |
40mb |
|
* IE6 en IE7 installed on different hardware, do not compare the results between browsers |
3. Avoid nested elements
Nesting sections, tables, optional sections and especially repeating sections/tables could lead to a extreme rendering time at the client.
4. Use multiple views
Try to spread controls over multiple views. This especially counts for complex controls like:
- Rich text editors
- Repeating sections/tables
- Drop down boxes
5. Minimize the numer of Rich text editors
Try to use regular textfields if possible
6. Avoid excessive use of validation/rules/conditional formatting
Try to prevent unnecessary roundtripping between the form browser and the server. There are several round trip switches available on controls. See the Browser Forms Tab on a given control to expose finer-grained options over the behavior. Note what the warning messages you receive say about the form's potential round trip behavior when admin deploying the form. It will tell you when multiple server roundtrips will be likely to occur when using your form.
7. Run Forms Services on a sererate server
Consider breaking out the server role of Forms Services to another machine on the MOSS farm. Services such as indexing and query serving, or high file I/O operations can really impact the ability of Forms Services to get a time slice and perform properly.
8. Set the optimal Session State
Forms Services supports 2 kinds of session state:
- Session State (data is saved in SQL through the SSP)
- Form View (data is saved in the form itself)
The following articles describe which is best for your situation:
http://technet2.microsoft.com/Office/en-us/library/3c4e8fb1-c3ce-4d27-8c65-6c4ab140f7051033.mspx?mfr=true
http://technet2.microsoft.com/Office/en-us/library/3728d1fa-c1db-4445-8d00-e26f9015dd951033.mspx?mfr=true
Be sure to check Tim Pashmans blogpost on IFS performance:
http://blogs.msdn.com/timpash/archive/2007/08/02/tips-and-tricks-for-tuning-forms-services-performance.aspx