In the new API the biggest change is to implement the only
data_sink_impl::put(span<temporary_buffer>) overload.
Encrypted file impl and sstables compress sink use fallback_put() helper
that generates a chain of continuations each holding a buffer.
The counting_data_sink in transport had mostly been patched to correct
implementation by the previous patch, the change here is to replace
vector argument with span one.
Most other sinks just re-implement their put(vector<temporary_buffer>)
overload by iterating over span and non-preemptively grabbing buffers
from it.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
The former helper is implemented like this:
future<> invoke_with_counting(fn) {
if (not_needed)
return fn();
return futurize_invoke(something).then([fn] {
return fn()
}).finally(something_else);
}
and all put() overloads are like
future<> put(arg) {
return invoke_with_counting([this, arg] {
return lower_sink.put(arg);
});
}
The problem is that with seastar API level 9, the put() overload will
have to move the passed buffers into stable storage before preempting.
In its current implementation, when counting is needed the
invoke_with_counting will link lower_sink.put() invocation to the
futurize_invoke(something) future. Despite "something" is
non-preempting, and futurize_invoke() on it returns ready future, in
debug mode ready_future.then() does preempt, and the API level 9 put()
contract will be violated.
To facilitate the switch to new API level, this patch rewrites one of
put() overloads to look like
future<> put(arg) {
if (not_needed) {
return lower_sink.put(arg);
}
something;
return lower_sink(arg).finally(something_else);
}
Other put()-s will be removed by next patch anyway, but this put() will
be patched and will call lower_sink.put() without preemption.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Before this change, new connections were handled in a default
scheduling group (`main`), because before the user is authenticated
we do not know which service level should be used. With the new
`sl:driver` service level, creation of new connections can be moved to
`sl:driver`.
We switch the service level as early as possible, in `do_accepts`.
There is a possibility, that `sl:driver` will not exist yet, for
instance, in specific upgrade cases, or if it was removed. Therefore,
we also switch to `sl:driver` after a connection is accepted.
Refs: scylladb/scylladb#24411
Moved files:
- generic_server.hh
- generic_server.cc
- protocol_server.hh
Fixes: #22112
This is a cleanup, no need to backport
Closesscylladb/scylladb#25090
