optimise remote client

velox/functions/remote/client/Remote.cpp

@@ -48,9 +48,8 @@ class RemoteFunction : public exec::VectorFunction {
       : functionName_(functionName),
         metadata_(metadata),
         serdeFormat_(metadata.serdeFormat),
-        serde_(getSerde(serdeFormat_)),
-        location_(metadata.location) {
-    boost::apply_visitor(*this, location_);
+        serde_(getSerde(serdeFormat_)) {
+    boost::apply_visitor(*this, metadata_.location);
 
     std::vector<TypePtr> types;
     types.reserve(inputArgs.size());
@@ -111,7 +110,7 @@ class RemoteFunction : public exec::VectorFunction {
               remoteRowVector, rows.end(), *context.pool(), &serde));
 
       std::unique_ptr<folly::IOBuf> responseBody = restClient_->invokeFunction(
-          boost::get<std::string>(location_), std::move(requestBody));
+          boost::get<std::string>(metadata_.location), std::move(requestBody));
 
       auto outputRowVector = IOBufToRowVector(
           *responseBody, ROW({outputType}), *context.pool(), &serde);
@@ -163,7 +162,7 @@ class RemoteFunction : public exec::VectorFunction {
       VELOX_FAIL(
           "Error while executing remote function '{}' at '{}': {}",
           functionName_,
-          boost::get<folly::SocketAddress>(location_).describe(),
+          boost::get<folly::SocketAddress>(metadata_.location).describe(),
           e.what());
     }
 
@@ -197,17 +196,16 @@ class RemoteFunction : public exec::VectorFunction {
 
   const std::string functionName_;
   const RemoteVectorFunctionMetadata metadata_;
-  remote::PageFormat serdeFormat_;
-  std::unique_ptr<VectorSerde> serde_;
-
-  boost::variant<folly::SocketAddress, std::string> location_;
+  folly::EventBase eventBase_;
 
   // Depending on the location, one of these is initialized by the visitor.
   std::unique_ptr<RemoteFunctionClient> thriftClient_{nullptr};
   std::unique_ptr<HttpClient> restClient_{nullptr};
 
-  folly::EventBase eventBase_;
+  remote::PageFormat serdeFormat_;
+  std::unique_ptr<VectorSerde> serde_;
 
+  // Structures we construct once to cache:
   RowTypePtr remoteInputType_;
   std::vector<std::string> serializedInputTypes_;
 };