> On Dec 4, 2017, at 3:46 PM, Martin Buchholz <marti...@google.com> wrote: > > The code in Long.fastUUID is indeed ugly. I've never heard of UUID > creation being a bottleneck. At Google it sometimes seems all our java > performance problems are with zip file manipulation.
At $MY_WORK, we never use Zip files, but indeed ran into some really nasty performance bottlenecks in UUID, and cared enough to whine about it and get it fixed ;) http://mail.openjdk.java.net/pipermail/core-libs-dev/2013-January/013494.html http://bugs.java.com/view_bug.do?bug_id=JDK-8006627 While I doubt a single string allocation is make or break for us (by far the bigger problem was the truly awful use of regex and tons of intermediate arrays) but UUID is a core data type and people expect it to be reasonably performant.
