Comment 4 for bug 2065501

This is hard to discuss against a somewhat old version running against a somewhat old version of Poppler.

Trying it out here, hitting enter always immediately cancels the old search and starts searching for the current term (as it should be). The timer will trigger a new search if the term has changed eventually, but you can always override it by pressing enter and the program will not wait until the timer is elapsed.

There is one unavoidable cause of delay and that is the search happening on one (or more) background threads: Before the search for the new term can being, the old one must be cancelled, i.e. there can never be two searches in progress at the same time. (There could be in principle, but they will just fit over locks inside Poppler.) This cancellation can only happen at page granularity due to the high overhead of setting up search for a given page.

But testing this here using the current version of qpdfview and Poppler version 24.03 with your document, this delay is barely noticeable, definitely subsecond, more likely around 100ms to 500ms.