I searched in google and stackoverflow for my problem, but couldn’t find a good solution. Below is the description,
Our Java web application displays search results from our local database and external webservice API calls. So, the search logic should combine these results and display it in the result page. The problem is, the external API calls return the results slower than our local DB calls. Performance is crucial for our search results and the results should be live i.e. we should not cache or persist the external results in our local DB. Right now, we are spanning two threads, one for the DB call and another one for the exteral API, and combine these results and display it on the screen. But it kills the performance of our application, particularly when we call more than one external APIs.
Is there any architectural solution for this problem?
Any help would be greatly appreciated.
Thanks.
You cannot display data before you have it.
1) You can display your local data and as they come, add via ajax other data.
2) And if there are repeated questions, you could cache external answers for short time (and display them with warning that they are old and that they will be replaced by fresh answer) and as soon as fresh anwer arrive, push new answer.
With at least 1), system will be responsive, with 2) usable answer can be available imediately, even if its not current.
btw, if external source take long to answer, are you sure that their answer is not stale (eg. if they gather some data and wait for rest, then what they gathered so far can go stale)? So maybe (and maybe not) short term persisting is not as bad as you think.