No, so maybe, we can leave it as it is.
We can add a counter and if the counter is greater than 1000 characters (for example), we stop the search
Yes, 1000 chars is quite enough.
Can you do some measurements, if this is really a performance problem?
add a timer to test it? and log out the time?
PS:
If we catch the new added char every time, then we can avoid counting the commas every time we do the calltip.
I mean, we can only check the new added char, if it is a commas, then we can increase the previous value.