use pqxx::pipeline for online update thread

controller/PostgreSQL.cpp

@@ -1337,6 +1337,7 @@ void PostgreSQL::onlineNotification_Postgres()
 	nlohmann::json jtmp1, jtmp2;
 	while (_run == 1) {
 		auto c = _pool->borrow();
+		auto c2 = _pool->borrow();
 		try {
 			fprintf(stderr, "%s onlineNotification_Postgres\n", _myAddressStr.c_str());
 			std::unordered_map< std::pair<uint64_t,uint64_t>,std::pair<int64_t,InetAddress>,_PairHasher > lastOnline;
@@ -1346,15 +1347,16 @@ void PostgreSQL::onlineNotification_Postgres()
 			}
 			
 			pqxx::work w(*c->c);
+			pqxx::work w2(*c2->c);
 
-			// using pqxx::stream_to would be a really nice alternative here, but
-			// unfortunately it doesn't support upserts.
-			// fprintf(stderr, "online notification tick\n");
-			std::stringstream memberUpdate;
-			memberUpdate << "INSERT INTO ztc_member_status (network_id, member_id, address, last_updated) VALUES ";
+			fprintf(stderr, "online notification tick\n");
+			
 			bool firstRun = true;
 			bool memberAdded = false;
 			int updateCount = 0;
+
+			pqxx::pipeline pipe(w);
+
 			for (auto i=lastOnline.begin(); i != lastOnline.end(); ++i) {
 				updateCount += 1;
 				uint64_t nwid_i = i->first.first;
@@ -1371,16 +1373,10 @@ void PostgreSQL::onlineNotification_Postgres()
 				std::string networkId(nwidTmp);
 				std::string memberId(memTmp);
 
-				const char *qvals[2] = {
-					networkId.c_str(),
-					memberId.c_str()
-				};
-
 				try {
-					pqxx::row r = w.exec_params1("SELECT id, network_id FROM ztc_member WHERE network_id = $1 AND id = $2",
+					pqxx::row r = w2.exec_params1("SELECT id, network_id FROM ztc_member WHERE network_id = $1 AND id = $2",
 						networkId, memberId);		
 				} catch (pqxx::unexpected_rows &e) {
-					// fprintf(stderr, "Member count failed: %s\n", e.what());
 					continue;
 				}
 
@@ -1388,32 +1384,30 @@ void PostgreSQL::onlineNotification_Postgres()
 				std::string ipAddr = i->second.second.toIpString(ipTmp);
 				std::string timestamp = std::to_string(ts);
 
-				if (firstRun) {
-					firstRun = false;
-				} else {
-					memberUpdate << ", ";
-				}
-
-				memberUpdate << "('" << networkId << "', '" << memberId << "', ";
+				std::stringstream memberUpdate;
+				memberUpdate << "INSERT INTO ztc_member_status (network_id, member_id, address, last_updated) VALUES "
+					<< "('" << networkId << "', '" << memberId << "', ";
 				if (ipAddr.empty()) {
 					memberUpdate << "NULL, ";
 				} else {
 					memberUpdate << "'" << ipAddr << "', ";
 				}
-				memberUpdate << "TO_TIMESTAMP(" << timestamp << "::double precision/1000))";
-				memberAdded = true;
-			}
-			memberUpdate << " ON CONFLICT (network_id, member_id) DO UPDATE SET address = EXCLUDED.address, last_updated = EXCLUDED.last_updated;";
+				memberUpdate << "TO_TIMESTAMP(" << timestamp << "::double precision/1000)) "
+					<< " ON CONFLICT (network_id, member_id) DO UPDATE SET address = EXCLUDED.address, last_updated = EXCLUDED.last_updated";
 
-			if (memberAdded) {
-				//fprintf(stderr, "%s\n", memberUpdate.str().c_str());
-				pqxx::result res = w.exec0(memberUpdate.str());
-				w.commit();
+				pipe.insert(memberUpdate.str());
+			}
+			while(!pipe.empty()) {
+				pipe.retrieve();
 			}
+
+			pipe.complete();
+			w.commit();
 			fprintf(stderr, "%s: Updated online status of %d members\n", _myAddressStr.c_str(), updateCount);
 		} catch (std::exception &e) {
 			fprintf(stderr, "%s: error in onlinenotification thread: %s\n", _myAddressStr.c_str(), e.what());
 		} 
+		_pool->unborrow(c2);
 		_pool->unborrow(c);
 
 		ConnectionPoolStats stats = _pool->get_stats();