On 15/06/2016 06:40, linbo liao wrote:
I am not sure, but looks it will cause the update other than insert. If
it is true, the only way is request includes IF NOT EXISTS, inform the
client it failed?
Thanks,
Linbo
Hi Linbo,
+1 with what Ben said, timestamp has a millisecond precision and is a
bad choice for making PK unicity.
If your client and server are on the same physical machine (both on same
computer or different vms on same hypervisor), insert duration can go
down to very few microseconds (2~3 on a recent computer).
Your insert will/should often become "update".
The reason is that update does not exists in cassandra, neither delete,
they are just "appends": append with same key for update or append of a
tombstone for delete.
You should try to use a timeuuid instead, it has a node, clock sequence,
a counter plus the timestamp part that you can get with cql functions,
and it exists for that use.
see here for the functions
https://docs.datastax.com/en/cql/3.3/cql/cql_reference/timeuuid_functions_r.html
--
best,
Alain
