Attached is an updated patch for this issue. This patch will not update the store estimated row count if no index scan was performed.
I tried to add a test to UpdateStatisticsTest to verify this, but ran into some trouble because the estimated row counts we get back from runtime statistics do not return this information directly. I did manually verify that we do not go thre setEstimatedRowCount for update statistics on a table with no index.
Regarding the use of internal interfaces in checkEstimatedRowCount, Myrna suggested that I clobber and build and make sure there were no build order issues and also that I make sure derbyTesting.jar didn't pick up the product classes. I checked both and the change seems ok from a build perspective.
I ran SelectivityTest and UpdateStatisticsTest and am running tests now but don't anticipate any problems since they don't exercise this code. Please review.