SharePoint Dragons

When working with external lists, a functionality of Business Connectivity Services (BCS), you’ve got to keep an eye on row limits.

Keep in mind two important limits:

1. The default Max is 2,000 items
2. The absolute Max is 25,000 items

Please see this link for more information: http://msdn.microsoft.com/en-us/library/hh144965.aspx

You should always define filters (it can be limit/comparison/wildcard filter) so that you can narrow your search and overcome others restrictions regarding a count of rows in the database. Especially when working with high volume of items, there might be cases in which you may have millions of items to pick, the bcs picker will show up to 200 items (this is a SharePoint restriction).

Please take a look at these articles about filter creation:

• Creating Comparison and Wildcard Filters for BCS in SharePoint Designer 2010
• How to: Define Filters for External Item Picker Controls

Also you may implement paging. Please take a look at these articles:

• How to use paging in BCS ?
• SharePoint 2010 External List Paging – Server Side
• Paging and sorting with BCS

This info was taken from forum discussion: http://social.technet.microsoft.com/Forums/en-US/sharepoint2010general/thread/9dba356c-65f3-49be-a452-6934baee7216

For ongoing work on this topic, check out the latest version of Wiki page http://social.technet.microsoft.com/wiki/contents/articles/9628.sharepoint-2010-best-practice-row-limits-in-external-lists.aspx