Salesforce Users are getting this error quite frequently: "To protect all customers from excessive usage and Denial of Service attack..."

Question

Salesforce users are getting the following error message:

To protect all customers from excessive usage and Denial of Service attacks, we limit the number of long-running requests that are processed at the same time by an organization. Your request has been denied because this limit has been exceeded by your organization. Please try your request again later.

What could be caused by?

Many thanks, AlbertoB

Answer 1

Salesforce allows only 10 long running requests per organisation. An Request that is running for more than 5 seconds is considered as long running request.

Following are the things which count against long running requests

• Apex - Classes/controllers, triggers
• SOQL
• Web Services - External and Apex Web Services
• Visualforce - ActionPoller, Ajax/Action-functions, JavaScript Remoting
• API - Calls to an Apex Class

How to prevent this

While designing the solution, try to use asynchronous requests in you VF pages, by using CONTINUATION class and Tune your SOQL queries so that they are executed for less amount of time.

You can find out the operation which is leading to this error by collecting and analyzing the debug log.

There is a very good article on developer.salesforce.com to avoid this.

Designing Force.com Applications That Avoid Hitting Concurrent Request Limits

Possible solutions.

• Convert synchronous processes to asynchronous processes. Batch Apex might be a viable alternative. Limit synchronous Web service callouts.
• Use the Streaming API instead of polling
• Tune SOQL and DML operations. Make sure that your queries are selective. Limit the number of records in your list views. Avoid data skew.