UUID_gen::create_time_safe() does not synchronize across cores. The
comment says that it assumes it runs on a single core. This is no
longer true, we can run urchin on many cores. This easily leads to
UUID conflicts with more than one core. Fix by adding a per-core
unique number to the node part of the UUID.
Convert Cassandra's UUIDGen class, which generates time-dependent UUID,
and parts of the java.util.UUID which I thought we need, to C++.
It is possible I missed some needed features of java.util.UUID that we'll
need to add later.
Also, part of the version-1 UUID is supposed to be node-unique (so that
if two nodes happen to boot at the same time and get a UUID at exactly
the same time, they still get different UUIDs). Cassandra uses for this
a hash function of the IP address, we should use in the future the MAC
address (from Seastar's network stack). But currently we just use 0.
Left a FIXME to fix that.
Signed-off-by: Nadav Har'El <nyh@cloudius-systems.com>
[avi: add to ./configure.py]
