Change RedisConnection::Query::value_type from String to std::variant<const char*,String>

Especially our history messages contain lots of hardcoded C string literals "like this one". At runtime, they get translated to pointers to constant global memory, const char*. String malloc(3)s and copies these data every time. In contrast, std::variant<const char*,String> just stores the address if any.

Author: Al2Klimov

lib/icingadb/icingadb-objects.cpp

@@ -710,12 +710,12 @@ void IcingaDB::InsertObjectDependencies(const ConfigObject::Ptr& object, const S
 			auto id (HashValue(new Array({m_EnvironmentId, actionUrl})));
 
 			if (runtimeUpdate || m_DumpedGlobals.ActionUrl.IsNew(id)) {
-				actionUrls.emplace_back(std::move(id));
+				actionUrls.emplace_back(id);
 				Dictionary::Ptr data = new Dictionary({{"environment_id", m_EnvironmentId}, {"action_url", actionUrl}});
 				actionUrls.emplace_back(JsonEncode(data));
 
 				if (runtimeUpdate) {
-					AddObjectDataToRuntimeUpdates(runtimeUpdates, actionUrls.at(actionUrls.size() - 2u), m_PrefixConfigObject + "action:url", data);
+					AddObjectDataToRuntimeUpdates(runtimeUpdates, id, m_PrefixConfigObject + "action:url", data);
 				}
 			}
 		}
@@ -725,12 +725,12 @@ void IcingaDB::InsertObjectDependencies(const ConfigObject::Ptr& object, const S
 			auto id (HashValue(new Array({m_EnvironmentId, notesUrl})));
 
 			if (runtimeUpdate || m_DumpedGlobals.NotesUrl.IsNew(id)) {
-				notesUrls.emplace_back(std::move(id));
+				notesUrls.emplace_back(id);
 				Dictionary::Ptr data = new Dictionary({{"environment_id", m_EnvironmentId}, {"notes_url", notesUrl}});
 				notesUrls.emplace_back(JsonEncode(data));
 
 				if (runtimeUpdate) {
-					AddObjectDataToRuntimeUpdates(runtimeUpdates, notesUrls.at(notesUrls.size() - 2u), m_PrefixConfigObject + "notes:url", data);
+					AddObjectDataToRuntimeUpdates(runtimeUpdates, id, m_PrefixConfigObject + "notes:url", data);
 				}
 			}
 		}
@@ -740,12 +740,12 @@ void IcingaDB::InsertObjectDependencies(const ConfigObject::Ptr& object, const S
 			auto id (HashValue(new Array({m_EnvironmentId, iconImage})));
 
 			if (runtimeUpdate || m_DumpedGlobals.IconImage.IsNew(id)) {
-				iconImages.emplace_back(std::move(id));
+				iconImages.emplace_back(id);
 				Dictionary::Ptr data = new Dictionary({{"environment_id", m_EnvironmentId}, {"icon_image", iconImage}});
 				iconImages.emplace_back(JsonEncode(data));
 
 				if (runtimeUpdate) {
-					AddObjectDataToRuntimeUpdates(runtimeUpdates, iconImages.at(iconImages.size() - 2u), m_PrefixConfigObject + "icon:image", data);
+					AddObjectDataToRuntimeUpdates(runtimeUpdates, id, m_PrefixConfigObject + "icon:image", data);
 				}
 			}
 		}

lib/icingadb/redisconnection.cpp

@@ -99,10 +99,14 @@ void LogQuery(RedisConnection::Query& query, Log& msg)
 			break;
 		}
 
-		if (arg.GetLength() > 64) {
-			msg << " '" << arg.SubStr(0, 61) << "...'";
+		if (auto str (std::get_if<String>(&arg)); str) {
+			if (str->GetLength() > 64) {
+				msg << " '" << str->SubStr(0, 61) << "...'";
+			} else {
+				msg << " '" << *str << '\'';
+			}
 		} else {
-			msg << " '" << arg << '\'';
+			msg << " '" << std::get<const char*>(arg) << '\'';
 		}
 	}
 }

lib/icingadb/redisconnection.hpp

@@ -39,6 +39,7 @@
 #include <set>
 #include <stdexcept>
 #include <utility>
+#include <variant>
 #include <vector>
 
 namespace icinga
@@ -53,7 +54,7 @@ namespace icinga
 	public:
 		DECLARE_PTR_TYPEDEFS(RedisConnection);
 
-		typedef std::vector<String> Query;
+		typedef std::vector<std::variant<const char*, String>> Query;
 		typedef std::vector<Query> Queries;
 		typedef Value Reply;
 		typedef std::vector<Reply> Replies;
@@ -667,7 +668,12 @@ void RedisConnection::WriteRESP(AsyncWriteStream& stream, const Query& query, bo
 	msg << "*" << query.size() << "\r\n";
 
 	for (auto& arg : query) {
-		msg << "$" << arg.GetLength() << "\r\n" << arg << "\r\n";
+		if (auto str (std::get_if<String>(&arg)); str) {
+			msg << "$" << str->GetLength() << "\r\n" << *str << "\r\n";
+		} else {
+			auto cstr (std::get<const char*>(arg));
+			msg << "$" << strlen(cstr) << "\r\n" << cstr << "\r\n";
+		}
 	}
 
 	asio::async_write(stream, writeBuffer, yc);