[PATCH v1 04/11] transport: co-routinize cql_server::connection::process_prepare

[Gleb Natapov]

---
transport/server.cc | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/transport/server.cc b/transport/server.cc
index fac3053c1b0..39bb3bc954e 100644
--- a/transport/server.cc
+++ b/transport/server.cc
@@ -1051,17 +1051,16 @@ future<std::unique_ptr<cql_server::response>> cql_server::connection::process_pr
tracing::add_query(trace_state, query);
tracing::begin(trace_state, "Preparing CQL3 query", client_state.get_client_address());

- return _server._query_processor.invoke_on_others([query, &client_state] (auto& qp) mutable {
- return qp.prepare(std::move(query), client_state).discard_result();
- }).then([this, query, stream, &client_state, trace_state] () mutable {
- tracing::trace(trace_state, "Done preparing on remote shards");
- return _server._query_processor.local().prepare(std::move(query), client_state).then([this, stream, trace_state] (auto msg) {
- tracing::trace(trace_state, "Done preparing on a local shard - preparing a result. ID is [{}]", seastar::value_of([&msg] {
- return messages::result_message::prepared::cql::get_id(msg);
- }));
- return make_result(stream, *msg, trace_state, _version);
- });
+ co_await _server._query_processor.invoke_on_others([query, &client_state] (auto& qp) mutable -> future<> {
+ (void)co_await qp.prepare(std::move(query), client_state);
});
+
+ tracing::trace(trace_state, "Done preparing on remote shards");
+ auto msg = co_await _server._query_processor.local().prepare(std::move(query), client_state);
+ tracing::trace(trace_state, "Done preparing on a local shard - preparing a result. ID is [{}]", seastar::value_of([&msg] {
+ return messages::result_message::prepared::cql::get_id(msg);
+ }));
+ co_return make_result(stream, *msg, trace_state, _version);
}

static future<process_fn_return_type>
--
2.45.2

[Avi Kivity]

On Tue, 2024-07-09 at 14:30 +0300, 'Gleb Natapov' via ScyllaDB development wrote:

---

 transport/server.cc | 19 +++++++++----------

 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/transport/server.cc b/transport/server.cc

index fac3053c1b0..39bb3bc954e 100644

--- a/transport/server.cc

+++ b/transport/server.cc

@@ -1051,17 +1051,16 @@ future<std::unique_ptr<cql_server::response>> cql_server::connection::process_pr

     tracing::add_query(trace_state, query);

     tracing::begin(trace_state, "Preparing CQL3 query", client_state.get_client_address());

 

-    return _server._query_processor.invoke_on_others([query, &client_state] (auto& qp) mutable {

-            return qp.prepare(std::move(query), client_state).discard_result();

-    }).then([this, query, stream, &client_state, trace_state] () mutable {

-        tracing::trace(trace_state, "Done preparing on remote shards");

-        return _server._query_processor.local().prepare(std::move(query), client_state).then([this, stream, trace_state] (auto msg) {

-            tracing::trace(trace_state, "Done preparing on a local shard - preparing a result. ID is [{}]", seastar::value_of([&msg] {

-                return messages::result_message::prepared::cql::get_id(msg);

-            }));

-            return make_result(stream, *msg, trace_state, _version);

-        });

+    co_await _server._query_processor.invoke_on_others([query, &client_state] (auto& qp) mutable -> future<> {

+            (void)co_await qp.prepare(std::move(query), client_state);

The cast to void isn't necessary. Before the coroutine it was, since future<whatever> doesn't convert to future<>, but the whatever isn't [[nodiscard]] so it can be dropped.

[Gleb Natapov]

Before the coroutine there was no void, there was discard_result(). Void
here is unnecessary, but it shows that the result is discarded.

> >      });
> > +
> > +    tracing::trace(trace_state, "Done preparing on remote shards");
> > +    auto msg = co_await
> > _server._query_processor.local().prepare(std::move(query),
> > client_state);
> > +    tracing::trace(trace_state, "Done preparing on a local shard -
> > preparing a result. ID is [{}]", seastar::value_of([&msg] {
> > +        return messages::result_message::prepared::cql::get_id(msg);
> > +    }));
> > +    co_return make_result(stream, *msg, trace_state, _version);
> >  }
> >  
> >  static future<process_fn_return_type>
> > --
> > 2.45.2
> >
>

--
Gleb.