Invalid set of rows requested, the source data of the report has been modified. - Explanation

When I first started using APEX I occasionally got the following pagination error message: Invalid set of rows requested, the source data of the report has been modified. reset pagination

At first I had no clue what was causing the error but after a while I finally figured it out. The best way to describe the error is to see exactly what is happening. Full example is here

Create a report

SELECT *
  FROM emp
 WHERE UPPER (ename) LIKE '%' || UPPER (:P800_LETTER) || '%'

When creating the report, change the number of rows from 15 to 5 for this example. This is important for this demonstration!

Now create a page item called P800_LETTER and a submit button who submits and redirect to P800.

If things went well you'd have a report that looks like this:

To illustrate the problem click on the Next pagination link so that we are seeing rows 6~10. Now, in the text box enter the letter I (this will restrict to 4 rows) and click submit. You should see the following error message:

To summarize what just happened, you initially requested a report with 14 rows and told APEX to display 5 at a time. When you clicked the Next pagination button you told APEX for the report you're currently looking at display rows 6~10. So now, if you were to refresh the page APEX would continue to show rows 6~10. When you filtered the report, by restricting to employees with the letter I in their name, you get a result with only 4 rows however APEX is still trying to display rows 6~10. I hope you now see the problem with this.

So now that we've demonstrated the problem, how do you fix it? Well there's several ways. To solve our current issue, on P800 in the submit branch we could check the reset pagination for this page. This means that each time you submit the page APEX will set the display rows back to 1~5.

There are also other ways to reset the pagination automatically. You can reset pagination in the URL: In the Clear Cache section you can enter RP to clear the page's cache. Please see the APEX documentation for more information. There is also a page process to reset the pagination. This allows you to also set the scope of the current page, multiple pages, or all pages.

I know the issue has come up to reset the pagination for an individual report rather than the entire page. I currently don't know of any method, however if you do please post!