General Information:

Power Shell script does not do a good job at the garbage collection and fails to remove the objects that have been used during the execution of the script. And the job of writing a clever script ends up in the hands of the script developer to make sure that the script does not cause a memory crunch or CPU crunch on the server. And most importantly a script developer should be aware that the script might end up running on multiple environments of difference scale. Hence the script written should be able to work with huge number of objects.

Issue:

I recently have been hit back very badly where the script prepared and tested in on one of my main DEV environments has caused server out of memory issue on the production. Below is a screenshot of such exception that has occurred during the execution of the script.

Here is the brief structure of the script that I have written and has caused a performance issue on the server in production

In the above script the highlighted area is the root cause that has taken a the 8 GB ram on the production server hosting 10361 sites. This line is created and bring the 10361 SPWeb objects to be created with global scope and our brought into server memory prior to actual execution. And also these objects remain in server memory throughout during the execution based on the scope of the dollar bets variable.

On more investigation I identified one way to prevent memory crunch on the server is to go with the Power Shell pipeline. But as you see the logic being executed in the above script cannot be completely moved into a pipeline execution model.

Resolution:

Hence I modified the script such that I only capture the essential and bare minimal things that are needed to create the objects when needed and have the objects removed once we are done with the object is used

Major highlights are:

1. I only captured the list of URLs that can be used to get the SPWeb object when need
2. Retrieved the SPWeb object right on demand
3. Removed the SPWeb object when we are done with it

This script work well efficiently and memory did not even touched the half 4 GB of the server memory site.

Lessons learned:

1.  PowerShell script does not have proper garbage collection
2. SharePoint object are huge. Get them or use them on Demand
3. Work with only Simple types(int, string, etc...) as long as possible

Below are the few places where I have encountered with this error:

1)      Navigate to Fast Query SSA from Central Admin à Manage services Application. Click on Fast Query SSA. Then click on “Fast Search Administration” link on the left hand side

2)      In a site collection navigate to site collection settings page. And on this page clicking on the links

• FAST Search Keywords
• FAST Search Site Promotion and demotion
• FAST Search user context

To resolve this please follow the below steps:

Adding Application Pool account to FASTSearchAdministrators group

The Application pool account of the Web Application should be granted access to the FAST search engine. On my single server machine installation I followed the below steps:

• Open Active Directory Users and Computers
• Nagivate to domain control in the tree view
• Click on Users and look for group names “FASTSearchAdministratorsGroup” (In generally this group can be found in local users and groups on the systems that have FASTsearch installed)

Note: if you cannot find a group by this name, you can create one with same name

• Double click the group navigate to Member tab,  click add and enter the account fo the app pool being used.

Note: Please add the App pool account used by central Admin too this group is not already present

Creating FASTSearchSearchSettingGroup for the site collection

Run the below command in FAST Search Shell to check if the FASTSearchSearchSettingGroup(which manages the keywords, promotions and demotions”) is created. If not created you would get the below error.

To create a group, run the below commands

• In SharePoint management shell: Get-Site http://sitecollectionURL | Select ID

• Now in FAST Search Shell run the below command as pass the ID as Name parameter

>>New-FASTSearchSearchSettingGroup –Name <<SitecollectionGUID>>

Adding Application Pool account to FASTSearchKeywordAdministrators group

The above steps would enable to access all the links, but you might still not able to access the “FAST Search user context” under site collection administrator links.

Couple of articles on internet have mentioned that Creating “FASTSearchKeywordAdministrators” groups and adding the required accounts to this group would enable access, but this hasn’t fixed my issue yet. So, the search is still on.