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From Earwin Burrfoot <>
Subject Re: Possible IndexInput optimization
Date Sun, 29 Mar 2009 11:01:51 GMT
> A while ago I tried overriding the read* methods in BufferedIndexInput like
> this:
> ............................
> I'm still surprised there was no performance improvement at all. Maybe
> something was wrong with my test and I should try it again...

For BufferedIndexInput improvement should be noticeable only when the
file you're reading is loaded completely into OS disk cache (which was
not your case, I guess). Even then, you're making a syscall for each
1Kb chunk, it could probably dominate 1K method calls.
But for RAMDirectory/MMapDirectory you're not reading disk (if disk
cache kicked in), and you're not making syscalls. I guess I should
stop asking around and try.

Kirill Zakharenko/Кирилл Захаренко (
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