>Is that a good idea? A user might do it 10 times to search in five years. And then it would still affect everyone. It's not an easy problem, I'm aware of that.

Not really, searching within a certain period of time implies the use of indexes, which is not the case if you search in the entire database. So, even by doing 10 searches, for one search per year going up to 10 years for example, will be much faster than allowing the user to search for a string as is, without any index, in the entire table.

>You might add a checkbox that does that type of search in the resulting cursor of the previous search. Then I could do a normal search on 'sys', resulting in perhaps 100 records. And do the full search of 'sys(1040)' within those 100 records.In order to minimize an overall performance drop, you might enable that checkbox only if the resulting cursor of the first search is less than, let's say, 500 records.

Yes, that is a good idea. Since I already have in memory the last search of every member, we could then add an exact string as is within that one and that would be immediate.