I was recently working on setting up an external content type to read from a SQL view and ran across this issue.  This error is thrown by SharePoint and will show up in the ULS viewer as one of several messages, the most common is:

Database response throttled. Maximum number of rows that can be read through the database system utility is 2000.

This feature is enabled by default to protect your SharePoint farm from Denial of Service Attacks, either by affecting your farm performance or by affecting the external system’s health due to large transactions.  You cannot make these changes from the farm Central Admin, but you can make them from PowerShell.  However, realize that this change happens at the service application proxy level, meaning that it’s all or nothing for the farm unless you’ve gone through the hassle of creating unique proxies for each tenant and associated those proxies to their web application.

Once you have the handle on the Proxy and the Rule, you can see what rules are set by typing $dbRule in the shell.

Here is the cut and paste for changing the limits:

$bdcProxy = Get-SPServiceApplicationProxy | where {$_.GetType().FullName -eq (‘Microsoft.SharePoint.BusinessData.SharedService.’ + ‘BdcServiceApplicationProxy’)}
$dbRule = Get-SPBusinessDataCatalogThrottleConfig -Scope Database -ThrottleType Items -ServiceApplicationProxy $bdcProxy
Set-SPBusinessDataCatalogThrottleConfig -Identity $dbRule -Maximum 10000 -Default 10000

And here are the fun things you can do and various rules can you set.  There are four ThrottleTypes and five Scopes:

ThrottleType

Meaning

Items

The number of records returned

Size

The amount of data returned, in bytes

Connections

The number of connections opened to the database, web service, or .NET assembly

Timeout

The time until an open connection is terminated, in milliseconds

Scope

Meaning

Global

Applies to Database, Web Service, WCF, and .NET Assembly Connectors (not to Custom Connectors)

Database

Applies to Database Connectors

WebService

Applies to Web Service Connectors

Wcf

Applies to WCF Connectors

Custom

Applies to Custom Connectors

Here’s a table of the rules that exist:

Global

Database

WebService

Wcf

Items

X

Size

X

X

Connections

X

Timeout

X

X

More information about the cmdlets can be found here:

Get-SPBusinessDataCatalogThrottleConfig

Set-SPBusinessDataCatalogThrottleConfig