Dealing with Large SPLists

burlo — Tue, 01 Jul 2008 05:59:11 +0000

There comes a time when you need to store information in SPlists that exceeds the Microsoft recommended value of 2000 items otherwise performance will degraded. I have come across this scenario a couple of times. An easy way around this problem may be to use folders in the list where each folder can also contain 2000 items or create views to limit the number of items to be displayed. However, this still may not fit your requirement. Best practices would suggest create a web service with its own business logic which hooks up to and SQL database. This is a bit of an over kill considering you can use the SharePoint API (and I do not suggestion to directly access the content database to store this information either. (The content database should not in any situation be directly accessed from the presentation layer; you must access the content database through the SharePoint object model)

This issue around restricting the number of items is not around the list itself but the rendering of the standard SharePoint page for displaying the list. This is demonstrated in the white paper “Working with large lists in Office SharePoint® Server 2007” by Steve Peschka ( http://technet.microsoft.com/en-us/library/cc262813(TechNet.10).aspx ), This is a really good article. Therefore if you are going to use a large SPList you need to develop you own abstract interface to display items within a large SPLists.

This now brings us to some tips and tricks for building and efficient high performing solution to retrieve and display data from large SPLists.

· If your list is not indexed the most efficient way is to use the PortalSiteMapProvider. GetCachedListItemsByQuery() method to get your selected items. PortalSiteMapProvider works very well when data is not constantly changing because PortalSiteMapProvider caches its data on the server and will need to go back to the database when data changes.

· If you are using a where clause in your query you may what to index your list. If this is the case then using the SPList. GetListItems () method will be more efficient with an indexed list.

· Indexing the list will cause item inserts and deletes to be slower so if there is a lot of item deleting and inserting of items to the list it may not be a good choice to index the list.

· When retrieving information from large lists you may want to do it asynchronously when rendering a web part by using Page.RegisterAsyncTask(). That way the rest of components on your page do not have to wait for your web part to retrieve data from the large list.

Using the SharePoint search API would be another efficient method of retrieving the data from the large lists, however the problem is that the list has to be crawled and indexed beforehand if changes are made to the list.

Burlo

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Dealing with Large SPLists